I doubt if it is rust. I am guessing that you have aluminum doors and what you are seeing is corrosion that has formed under the paint. To repair it, all of the corrosion must be removed and then the surfaces primed and painted to match. You can get the paint formulas by contacting Barbara O'donnell "b.odonnell@industrialfinishes.com" at Industrial Finishes, inc. She will give you the formula to have your paint matched at the nearest facility that handles BASF paint.
You will need to send her all of the information about your coach including the paint scheme and colors.
