diff --git a/phinx/src/Phinx/Db/Adapter/MysqlAdapter.php b/phinx/src/Phinx/Db/Adapter/MysqlAdapter.php
index 37710a6..f882fb5 100644
--- a/phinx/src/Phinx/Db/Adapter/MysqlAdapter.php
+++ b/phinx/src/Phinx/Db/Adapter/MysqlAdapter.php
@@ -211,20 +211,17 @@ public function createTable(Table $table)
 
         // Add the default primary key
         $columns = $table->getPendingColumns();
-        if (!isset($options['id']) || (isset($options['id']) && $options['id'] === true)) {
-            $column = new Column();
-            $column->setName('id')
-                   ->setType('integer')
-                   ->setIdentity(true);
 
-            array_unshift($columns, $column);
-            $options['primary_key'] = 'id';
+        if (!isset($options['id']) || (isset($options['id']) && $options['id'] === true)) {
+            $options['id'] = 'id';
+        }
 
-        } elseif (isset($options['id']) && is_string($options['id'])) {
+        if (isset($options['id']) && is_string($options['id'])) {
             // Handle id => "field_name" to support AUTO_INCREMENT
             $column = new Column();
             $column->setName($options['id'])
                    ->setType('integer')
+                   ->setSigned(isset($options['signed']) ? $options['signed'] : true)
                    ->setIdentity(true);
 
             array_unshift($columns, $column);