Try these three links, the pics will help you. You may have to do a bit of prying on the wing piece (the piecethat goes under the headlights) at the same time you're pressing on the plastic release clip.
Hth.
http://bmwe34m5.com/faqs/?theme=1&le...nt_id_select=3
http://www.bimmer.info/ed/headlight/
http://www.bimmer.info/ed/hid/