Phone Connections to BMW "Business Radio System"

[Ra1der]

Hi I have 523 SEI Auto with BMW Business Entertainment System, (Basic CD changer in Boot, Radio, Tape and Tuner). When I bought the car there was a car phone cradle that has a separate speaker and pauses and mutes the stereo when in operation.

I have been trying to find out information that will tell me the connections to the radio system for a new car kit, which will hopefully allow me to use the stereo and its speakers and still pause the audio system.

So don't suppose anyone has any details or knows where I can get them?