Custom View or Full Image for UITabBarItem

[coding]

Hello,

I wonder how I can realize a custom UITabBar where the UITabBarItems are fully changeable. For example to get rid of the title and image, which are the only elements to be changed an replace them with a custom view which overlays the entire UITabBarItem.

An example what I mean, for those who still don't know what I mean is the facebook app:

http://farm2.static.flickr.com/1368/...9b5fccfb3e.jpg

There are 4 Tab bar elements (Home, Profile, Friends, Inbox) (yes I know, this is not up2date) for making different views visible.
Does anyone have a clue how this is realized?
I suppose it is not done with a common UITabBar?

Thanks in advance for your help.

kind regards, Phil