Are you doing the following procedure?
1)open valve, then depress clutch
2)close valve, then release clutch
3)Repeat steps 1 & 2 until no more air comes out of the tube attached to the bleeder valve.
4)Check reservoir and add fluid as needed.
Try the instructions on this site:
http://www.billswebspace.com/BMWCDVMod.html
Let us know if that helps!