Looks great!
If it's HDPE plastic, which I *think* these things are, you may find the paint not lasting very long. Nothing much sticks to HDPE and for painting it, I believe you need a chlorinated polyolefin primer which isn't in your typical rattle can paint. If it does stand up, please post a year or two or three down the road because if it does work, I'll do the same with ours.
I've been using 303 protectant on our black cover. Makes it look snappy again, but it's backed to being faded in short order. :(
Fading stuff on RV exteriors seems to just be part of owning an RV... Sad!