W880i Button Layout

I recently bought a replacement housing for my W880i, and the keypad that came with it has two buttons which are different. I have a shortcut button instead of a cancel call button and a little headphone button instead of answer phone button. I flashed my phone with generic europe_2 firmware and generic_uk filesystem. It works perfectly except where it should be sending me to my walkman app when I press my headphone button, it sends me to my internet browser. Can someone help me change what that button is assigned to? I have no idea where to start...

thanks!