How to put a view on the back button of navigation bar?

Hey guys, I am wondering how to put a view on the back button of navigation bar? Not on title view, but on the back button. It seems like to me that the back button is a UIBarButtonItem, which doesn't inherite UIView... Help please!

Thanks!

From stackoverflow

• You can do it programmatically using initWithCustomView.

  AtomicElementViewController.m has a good example of this.