Hey, welcome it's not too bad a job but a lot of screws and bolts all the way round. I'm sure there is at least 4 underneath however if you look at RealOEM they have diagrams of the fixtures for the bumper which may help. I've never removed the rear just inspected it whilst up on a ramp.
This maybe of use to you
http://www.realoem.com/bmw/partgrp.do?model=LM51&mospid=51402&hg=51&lang=en