Rotate NGUI Element with Touch Moves

Hi all, I am trying to make a steering wheel. I did it onGui with drawing textures. Now i want to do it with Ngui. But i couldnt figure out how to rotate steering wheel based on my touch moves. I couldnt find any tutorial about how to work with touch phases. What exactly i want to do is if my touch (in a spesifict rect) moves around a pivot point, i want to rotate steering wheel as u can imagine. I have no idea how to do that with NGUI. Any help, any tutorial link, any document to start would be great. (Sorry for my English btw:))