iOS Facebook integration issue.

I'm attempting to integrate Facebook into my application by writing plugins to communicate between Unity and XCode. Since this is my first plugin. I started out simple, implementing the Facebook Login and Logout functionality. I'm able to make my application interact with Facebook; performs fast-app switch upon hitting GUI button to prompt login, etc.

But after Facebook authenticated my account credentials, it performs another fast-app switch to transit back into my application. For some strange reason, the Activity swaps to my application's splash screen for a very short instance and then it resumes the activity. (Well, this looks pretty ugly :( ). Am I doing something wrong? Can I avoid this somehow or at least HIDE it? Because it gives a really unprofessional feel when it does this...

I have read the tutorial manuals on Facebook Developers webpage and modifed the AppController.h/mm built from Unity with additional code for instance

     // New code taken from Facebook Developer webpage.
     - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
     {
        return [[FBSession activeSession] handleOpenUrl:url];
     }
     
     // For iOS 4
     // Callback order:
     //   applicationDidResignActive()
     //   applicationDidEnterBackground()
     - (void)applicationDidEnterBackground:(UIApplication *)application
     {
         printf_console("-> applicationDidEnterBackground()\n");
     }
     
     ......

Please do not ask me to refer to Assets Store such as Prime31. I heard that it is good, worth buying and cheap. But I really cannot afford to buy any plugins/add-on. I think I'm almost there, just couldn't figure out what other steps I have missed out. Anybody out there is willing to provide me with any suggestions or guidance?

Thank you.

I'm working on Unity 3.5.7 with Facebook SDK v3.5.1