Here's a little trick they don't talk about too much. Buy some MEK (methyl ethyl ketone) and wearing an appropriate mask and gloves, wet a clean, white rag and carefully rub the wetted rag over the entire, previously well cleaned surface and into all the nooks and crannies. This performs the same purpose in softening the plastic and aiding adhesion. I did all my interior panels this way and used the SEM Landau black and they look like new and there have been NO adhesion issues. Apply the paint, as mentioned, in light coats until you get full, even coverage. I applied the paint pretty much as soon as the surface had fully dried after the MEK application. Sat them in the sun until they were dry and away you go! Good luck.
PS- I used soap and water and a fine 3M pad to clean the parts initially. Don't rub too hard as well.