I installed the resler module permanantly in my E46 M3 by making a new lead. This plugs into th existing CD changer plug, and splits into two new plugs, one goes into my intravee, th eother into the resler. I just have to get the usb lead out of the cubby hole to us it.

The following is from my post on the intravee forum:-
For anyone who is interested, and to save the BMW parts department some work, these are the part numbers I used.

B61.13.6.931.929 Pin Terminal (connector to accept ibus plug from CD)
B61.13.0.006.664 Pin Contact (3 of these connect into above to make a lead)
B61.13.8.377.072 Plug (Same as ibus plug - I used two of these)
B61.13.0.006.663 Term (3 of these go into each of the plugs above - I got 6 of these)

I then soldered and taped the leads together. So the original ibus plugs in to the socket, and I have two ibus plugs, one for the intravee, and one for the resler board.