I have on my blog a tutorial for that http://gtadriftersdriftblog.blogspot.com/2009/11/tutorial-second-step-how-to-add-part-on.html look from Step 22 on, you can also download the tutorial if you don't have Internet when u need it http://www.4shared.com/file/149810461/252b6b6b/TUTO_2ND_STEP_-_ADD_A_PART.html