There is a kit to do excatly what you say. Let me try to find you a link...
edit: Alright, what you need is item (12) here: RealOEM.COM * BMW E46 330Ci STORING PARTITION MOUNTING PARTS
I believe you would have to get the one that is intended for cars with navigation. If I were you, I would call the dealership, or a place like Pelican Parts - Porsche Parts & BMW Parts - Automotive Parts and Accessories - Porsche & BMW
and give them that part number, tell them exactly what car you have, what you want to do, and if that part will work -- all this just to be sure you don't spend $50 for nothing.