Ah, gotcha.
Unfortunately I'm not all too well versed in your vehicle, but can offer an option for you. Here at NICO, we have Factory Service Manuals (FSM) available free to members. Here's the link to the A/V section of the FSM for your car
AUDIO, VISUAL & NAVIGATION SYSTEM With any luck you may find the info you're looking for.
BTW, I moved your topic to the Q70 where it will attract the attention of people that are more familiar with your car. The A/V forum is pretty dead.