The key to a successful job is to make sure you prepare the vinyl or plastic really well before even shaking the spray can.
My preparation consisted of:
* Scrubbing with a scourer and hot water (and a touch of dishwashing liquid);
* Dry with a clean towel, let stand overnight to make sure it's properly dry;
* Cleaning with K&N Wax and Grease remover. VHT advise the use of their own prep and clean, however it's impossible to get from the stores I visited;
* Wipe off with a damp cloth to make sure that all residue is gone;
Make sure you pay particular attention to the grooves in the trim. The dirt and crap loves to live in there!
After that, make sure you don't leave your fingerprints all over the vinyl! Oh year, the door lock ring was taken out after this picture was taken.