http://www.realoem.com/bmw/enUS/show...diagId=51_8215
Hope the link works. If not, go to RealOEM, get your car entered, look for trim parts, then the trunk. It'll give you a good visual of what the piece looks like inside and a better idea of how it goes together / comes apart.
Looks like it's a matter of just pulling. Specific panel trim tools (Amazon) can help, a set of plastic pry bars basically. Will get you closer to the piece to pull and make it less likely to break.