Adding a button to the default incoming call screen in Android

Question

I'm in the process of developing an Android app for which I need to add a button on the incoming call screen. Is it possible to add a new button to the existing incoming call screen or should I create a custom screen specific to my app?

Edit: I want to add a button in addition to the Answer and Decline buttons in the screen that appears when there is an incoming call.

Answer 1

I was looking for the same funcionality and found this open source project, http://code.google.com/p/incomingcallplus/

Haven't played with it yet, but seems to do what you're looking for.