There really is no secret that I know of to remove this. After you get the screws removed it should just come off. I would guess it has some windshield sealant and other gunk keeping it on. I would just use as much finesse as possible and above all, take your time. Some sort of a wide scraper should do it, plastic if possible. Gently run it down (flat) between the trim and the body to separate the trim from the adhesive . Hope this helps, maybe someone else will chime in with better advice. And of course it is mated with the two corner trim stainless pieces as well, just saying.
Ray,