Actually it might be better to let a shop do it, for these reasons. The molded plastic used, will require a special primer that helps the paint adhere ( i cant remember what its called) secondly the paint needs certain type of mix to stay "clean" free of chipping and falling apart. I wish I could be of more help as far as what 'exactly' is needed. If I can get a hold of my grandfather (a body man for 50 years) who can and has done these things for others, I will repost with the proper info. But with that said I do know that they are fairly expensive and take someone who does know how to mix it 'right'. So IMHO I would just let a shop do it.
Russell