I thought people put vinyl on to avoid painting. If you got some bad color, check into the warranty. Early vinly products had some color and fading problems but it is getting better now.
I think you are better off replacing it like Jay says. Vinyl has the color bonded to it when made and a paint coating won't have that good of a bond but do what you want. Buy some new vinyl and replace it. The hard part is laying it out and someone else has already done that. Just look at the old stuff and watch how you take it and the trim off. Cut the new trim just like the old. You can probably use the same backer and do one side at a time. Good luck.