WWW fails to load assetbundle in iOS

I'm having problems to get an assetbundle, I already build it with the iPhone target so that should not be the problem.

My method looks like this

         public static string AssetBundleURL
         {
             get
             {
                 if (Application.platform == RuntimePlatform.WindowsWebPlayer || Application.platform == RuntimePlatform.OSXWebPlayer)
                     return Application.dataPath + "/assetbundles/";
                 else if(Application.platform == RuntimePlatform.IPhonePlayer)
                     return "file://" + Application.dataPath + "/Raw/assetbundles/";
                 else
                     return "file://" + Application.dataPath + "/../assetbundles/";
             }
         }

I start the simulation and I get the following path:

"file:///Users/dev/Library/Application Support/iPhone Simulator/5.0/Applications/E01747A0-F487-4415-825B-6095FDCBEE6E/rb.app/Data/Raw/assetbundles/ios.assetbundle"

I already checked if the file was on that path... and it's there but for some reason www gives an error != null when I print it... then I get bad URL

Any idea?

Ther is already a question about this:

http://answers.unity3d.com/questions/163421/about-loading-assetbundle-in-iphone.html