Today @obert kind enough to measure his trunk handle and the trunk handle itself looks like the same size as the E90 one. Mounting the camera like the F30 is option one once you drill a square hole to the right of the camera.
Option two is to take one of the halogen number plate lights and to cut out a hole in the center.
I have aftermarket LED lights that look bad with one of them not plugged in. I think to make it look good I will go back to the halogens.