Selectively push part of UIViewController

In the Twitter for iPh开发者_如何学运维one application (the app formerly known as Tweetie) there is nifty effect when pushing from the tweet view controller to the account view controller.

The name of the account, the profile image and the users name stay fixed in position while the navigation controller animates pushing a new controller on to the stack. Does anyone know how this is achieved?

I've tried pushing a non-animated viewcontroller on to the stack and overriding the viewDidAppear:animated: method but met with no luck.

It's possible those view items are not subviews of the viewcontroller's view. They could be subviews of a higher level view or subviews of the window or another window.