Most of the information you need is here:

http://www.benzworld.org/forums/audio-telematics-forum/1313173-how-guide-cell-phone-upgrades-plug.html

The item needed for Bluetooth that's being discussed is commonly called "puck with tail."

Use of this item requires the original 2001 phone system be installed and upgraded if needed for digital replacement of analog.

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles