It was part of a Becker navigation kit, you can buy the facia and frame separately though, part numbers here (6 & 7):thats much much better. got the part number for it?
http://www.realoem.com/bmw/showparts.do?model=BD32&mospid=47617&btnr=65_1642&hg=65&fg=95
It's possible you might need to trim the frame a bit depending which head unit you have.