BMW Bluetooth

[Skids]

I have an E39 BMW that had a Motorola V50 mobile phone system factory fitted. I'm trying to retrofit bluetooth with the OEM components apart from the main wiring adapter loom. I have half of it and I've found various sites detailing the pin connections I need. I've done this but the computer says I need to activate the phone. Pairing button has no effect except to initiate voice control. Have I done something wrong or does my car need reprogramming to accept the bluetooth module?