Bug on winEvents for binding the event 'beforeunload'

When I use winEvents on a brite view,
When I bind the event beforeunload thanks the 'winEvents' of briteView, nothing appened.
With the same function binding directly, with 'on', it's work.

Below, an example of code :

beforeUnloadFn = function(e){
        var confirmationMessage = "\o/";
        (e || window.event).returnValue = confirmationMessage;     //Gecko + IE
        return confirmationMessage; 
      }
      brite.registerView('Test', {
        create: function(){
          return '<div style="background-color:red;height:50px;width:50px;"></div>'
        },
        winEvents: {
          //  No effect
          'beforeunload': beforeUnloadFn
        }
      });
      $(document).ready(function(){
        brite.display('Test', 'body');
        //  work
        //$(window).on("beforeunload", beforeUnloadFn);
      });

I get the last brite-snapshot version. And I reproduce the bug on firefox and chrome.
I was not clear on my example.
When I bind the event beforeunload with on of jQuery, it's work :

beforeUnloadFn = function(e){
  var confirmationMessage = "\o/";
  (e || window.event).returnValue = confirmationMessage;     //Gecko + IE
  return confirmationMessage; 
}
$(document).ready(function(){
  $(window).on("beforeunload", beforeUnloadFn);
}

Here the fiddle : http://jsfiddle.net/KGFke/ . If you click on run, you will see a popup.
And when I use the brite event it doesn't work :

beforeUnloadFn = function(e){
  var confirmationMessage = "\o/";
  (e || window.event).returnValue = confirmationMessage;     //Gecko + IE
  return confirmationMessage; 
}
brite.registerView('Test', {
  create: function(){
    return '<div style="background-color:red;height:50px;width:50px;"></div>'
  },
  winEvents: {
    //  No effect
    beforeunload': beforeUnloadFn
  }
});
$(document).ready(function(){
  brite.display('Test', 'body');
}

Here the fiddle : http://jsfiddle.net/MHf2j/ . If you click on run, no popup appears.