Can I curl down a transparent overlay image that looks transparent in the animation?

Currently I am using UIView's +transitionWithView method to add an overlay by adding a UIImageView that contains a transparent image as a subview of my main view. I am using the curl down transition option. The problem is that this transitioning method is opaque, that is it is curling down the "after" view on top of the "before" view. Is开发者_如何转开发 there a way to curl down and peel off a transparent image like transparency sheets for an overhead projector?

Thanks!