Nib file does not load from UITabBarViewController

I've tried almost all the possible permutations... I'm trying to make something like this:

http://www.amateurinmotion.com/articles/2009/01/24/creating-uitabbarcontroller-based-app-using-interfacebuilder.html

It's fairly simple and I tried running the program and it works. Now I'm trying to customise my current app so that it uses IB to load the xib file. My view hierarchy is like this:

So what I did is I selected the view controller and then 开发者_开发百科I go to the view controller attributes and set the nib name to be a nib file name. I also changed the view controller identity to load my custom class.

I fixed it... It turns out that I have an extra layer of UIView in my view controllers... All good now!