I do not know how that looks like, here some instructions
http://www.carstereohelp.com/stereoremovalBmwZ3Str.htm
http://www.pelicanparts.com/bmw/tech.../E36-Radio.htm
for the one on my CD43 I needed a pentagon tool
http://cgi.ebay.com/Bmw-Pentagon-Wre...item3361a7ab7a
http://www.radiomanrepair.com/removal.htm
http://www.mobileinformationlabs.com...oval_tools.htm