UINavigationController - how to not animate when popping using backbutton?

This ought to b开发者_开发知识库e simple but I just can't figure this one out:

The default behaviour when clicking the backbutton in a UINavigationController is that the current view gets popped with an animation. How can I override the default behaviour so that this transition is not animated?

[self.navigationController popToViewController:viewController animated:NO];

http://developer.apple.com/library/ios/documentation/uikit/reference/UINavigationController_Class/Reference/Reference.html#//apple_ref/occ/instm/UINavigationController/popToViewController:animated: