diff --git a/ActiveDirectory/Repositories/ActiveDirectoryProviderUserRepository.cs b/ActiveDirectory/Repositories/ActiveDirectoryProviderUserRepository.cs
index da6d41e..577c061 100644
--- a/ActiveDirectory/Repositories/ActiveDirectoryProviderUserRepository.cs
+++ b/ActiveDirectory/Repositories/ActiveDirectoryProviderUserRepository.cs
@@ -1,134 +1,135 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.Composition;
-using System.Configuration;
-using System.DirectoryServices.AccountManagement;
-using System.Linq;
-using System.Security.Cryptography.X509Certificates;
-using System.Web.Profile;
-
-using Microsoft.IdentityModel.Claims;
-using Thinktecture.IdentityServer.TokenService;
-using Thinktecture.IdentityServer.Repositories;
-
-using ThinkTecture.IdentityServer.Contrib.ActiveDirectory.Configuration;
-
-namespace ThinkTecture.IdentityServer.Contrib.ActiveDirectory.Repositories
-{
-    public class ActiveDirectoryProviderUserRepository : IUserRepository
-    {
-        private const string ProfileClaimPrefix = "http://identityserver.thinktecture.com/claims/profileclaims/";
-
-        [Import]
-        public IClientCertificatesRepository Repository { get; set; }
-
-        public ActiveDirectoryProviderUserRepository()
-        {
-            Container.Current.SatisfyImportsOnce(this);
-        }
-
-        public bool ValidateUser(string userName, string password)
-        {
-            using (PrincipalContext context = GetPrincipalContext())
-            {
-                return context.ValidateCredentials(userName, password);
-            }
-        }
-
-        public bool ValidateUser(X509Certificate2 clientCertificate, out string userName)
-        {
-            return Repository.TryGetUserNameFromThumbprint(clientCertificate, out userName);
-        }
-
-        public IEnumerable<string> GetRoles(string userName, RoleTypes roleType)
-        {
-            var returnedRoles = new List<string>();
-
-            using (PrincipalContext context = GetPrincipalContext())
-            {
-                // find the user in the identity store
-                UserPrincipal user = UserPrincipal.FindByIdentity(context, userName);
-
-                // get the groups for the user principal and
-                // store the results in a PrincipalSearchResult object
-                PrincipalSearchResult<Principal> results = user.GetGroups();
-
-                results.ToList().ForEach(result => returnedRoles.Add(result.Name));
-            }
-            return returnedRoles;
-        }
-
-        public IEnumerable<Microsoft.IdentityModel.Claims.Claim> GetClaims(IClaimsPrincipal principal, RequestDetails requestDetails)
-        {
-            var claims = new List<Claim>();
-
-            using (PrincipalContext context = GetPrincipalContext())
-            {
-                var userName = principal.Identity.Name;
-
-                // find the user in the identity store
-                UserPrincipal user = UserPrincipal.FindByIdentity(context, userName);
-
-                // email address
-                string email = user.EmailAddress;
-                if (!String.IsNullOrEmpty(email))
-                {
-                    claims.Add(new Claim(ClaimTypes.Email, email));
-                }
-
-                // roles
-                GetRoles(userName, RoleTypes.Client).ToList().ForEach(role => claims.Add(new Claim(ClaimTypes.Role, role)));
-
-                // profile claims
-                if (ProfileManager.Enabled)
-                {
-                    var profile = ProfileBase.Create(userName, true);
-                    if (profile != null)
-                    {
-                        foreach (SettingsProperty prop in ProfileBase.Properties)
-                        {
-                            string value = profile.GetPropertyValue(prop.Name).ToString();
-                            if (!String.IsNullOrWhiteSpace(value))
-                            {
-                                claims.Add(new Claim(ProfileClaimPrefix + prop.Name.ToLowerInvariant(), value));
-                            }
-                        }
-                    }
-                }
-            }
-
-            return claims;
-        }
-
-        public IEnumerable<string> GetSupportedClaimTypes()
-        {
-            var claimTypes = new List<string>
-            {
-                ClaimTypes.Name,
-                ClaimTypes.Email,
-                ClaimTypes.Role
-            };
-
-            if (ProfileManager.Enabled)
-            {
-                foreach (SettingsProperty prop in ProfileBase.Properties)
-                {
-                    claimTypes.Add(ProfileClaimPrefix + prop.Name.ToLowerInvariant());
-                }
-            }
-
-            return claimTypes;
-        }
-
-        private PrincipalContext GetPrincipalContext()
-        {
-            var section = ConfigurationManager.GetSection(ActiveDirectoryConfigurationSection.SectionName) as ActiveDirectoryConfigurationSection;
-
-            string container = string.IsNullOrEmpty(section.Container) ? null : section.Container;
-            string userName = string.IsNullOrEmpty(section.UserName) ? null : section.UserName;
-            string password = string.IsNullOrEmpty(section.Password) ? null : section.Password;
-
-            return new PrincipalContext(section.ContextType, section.DomainName, container, userName, password);
-        }
-    }
-}
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.Configuration;
+using System.DirectoryServices.AccountManagement;
+using System.Linq;
+using System.Security.Cryptography.X509Certificates;
+using System.Web.Profile;
+
+using Microsoft.IdentityModel.Claims;
+
+using Thinktecture.IdentityServer.TokenService;
+using Thinktecture.IdentityServer.Repositories;
+
+using ThinkTecture.IdentityServer.Contrib.ActiveDirectory.Configuration;
+
+namespace ThinkTecture.IdentityServer.Contrib.ActiveDirectory.Repositories
+{
+    public class ActiveDirectoryProviderUserRepository : IUserRepository
+    {
+        private const string ProfileClaimPrefix = "http://identityserver.thinktecture.com/claims/profileclaims/";
+
+        [Import]
+        public IClientCertificatesRepository Repository { get; set; }
+
+        public ActiveDirectoryProviderUserRepository()
+        {
+            Container.Current.SatisfyImportsOnce(this);
+        }
+
+        virtual public bool ValidateUser(string userName, string password)
+        {
+            using (PrincipalContext context = GetPrincipalContext())
+            {
+                return context.ValidateCredentials(userName, password, ContextOptions.Negotiate);
+            }
+        }
+
+        public bool ValidateUser(X509Certificate2 clientCertificate, out string userName)
+        {
+            return Repository.TryGetUserNameFromThumbprint(clientCertificate, out userName);
+        }
+
+        public IEnumerable<string> GetRoles(string userName, RoleTypes roleType)
+        {
+            var returnedRoles = new List<string>();
+
+            using (PrincipalContext context = GetPrincipalContext())
+            {
+                // find the user in the identity store
+                UserPrincipal user = UserPrincipal.FindByIdentity(context, userName);
+
+                // get the groups for the user principal and
+                // store the results in a PrincipalSearchResult object
+                PrincipalSearchResult<Principal> results = user.GetGroups();
+
+                results.ToList().ForEach(result => returnedRoles.Add(result.Name));
+            }
+            return returnedRoles;
+        }
+
+        virtual public IEnumerable<Claim> GetClaims(IClaimsPrincipal principal, RequestDetails requestDetails)
+        {
+            var claims = new List<Claim>();
+
+            using (PrincipalContext context = GetPrincipalContext())
+            {
+                var userName = principal.Identity.Name;
+
+                // find the user in the identity store
+                UserPrincipal user = UserPrincipal.FindByIdentity(context, userName);
+
+                // email address
+                string email = user.EmailAddress;
+                if (!String.IsNullOrEmpty(email))
+                {
+                    claims.Add(new Claim(ClaimTypes.Email, email));
+                }
+
+                // roles
+                GetRoles(userName, RoleTypes.Client).ToList().ForEach(role => claims.Add(new Claim(ClaimTypes.Role, role)));
+
+                // profile claims
+                if (ProfileManager.Enabled)
+                {
+                    var profile = ProfileBase.Create(userName, true);
+                    if (profile != null)
+                    {
+                        foreach (SettingsProperty prop in ProfileBase.Properties)
+                        {
+                            string value = profile.GetPropertyValue(prop.Name).ToString();
+                            if (!String.IsNullOrWhiteSpace(value))
+                            {
+                                claims.Add(new Claim(ProfileClaimPrefix + prop.Name.ToLowerInvariant(), value));
+                            }
+                        }
+                    }
+                }
+            }
+
+            return claims;
+        }
+
+        virtual public IEnumerable<string> GetSupportedClaimTypes()
+        {
+            var claimTypes = new List<string>
+            {
+                ClaimTypes.Name,
+                ClaimTypes.Email,
+                ClaimTypes.Role
+            };
+
+            if (ProfileManager.Enabled)
+            {
+                foreach (SettingsProperty prop in ProfileBase.Properties)
+                {
+                    claimTypes.Add(ProfileClaimPrefix + prop.Name.ToLowerInvariant());
+                }
+            }
+
+            return claimTypes;
+        }
+
+        private PrincipalContext GetPrincipalContext()
+        {
+            var section = ConfigurationManager.GetSection(ActiveDirectoryConfigurationSection.SectionName) as ActiveDirectoryConfigurationSection;
+
+            string container = string.IsNullOrEmpty(section.Container) ? null : section.Container;
+            string userName = string.IsNullOrEmpty(section.UserName) ? null : section.UserName;
+            string password = string.IsNullOrEmpty(section.Password) ? null : section.Password;
+
+            return new PrincipalContext(section.ContextType, section.DomainName, container, userName, password);
+        }
+    }
+}