I was hoping to do the same to mine this weekend...
until I heard is meant to be RAINING.

Oh well.
What I was planning, based on several peoples advice:
-Rub down to key paint and remove all loose stuff
-Clean up soapy water, mask trim strips up
-Paint with a plastic / bumper flexible primer x 2 - 3 layers (hour between coats)
-Leave for 24hours
-Paint with a couple of layers of paint mixed to colour
-Leave for 24hours
-Apply laquer and hopefully end up with something pretty good!
Good luck, let us know how you get on