Hi Rostman and richpu,
Sorry for late reply, Yes the CVBS video signal is fed directly into the Nav computer in the boot.
The video signal wire goes to pin 3 and the ground/screen goes to pin 11.
The connector is X1313 which is the 18 pin connector on the far right of the unit looking from the back.
Im not sure if anything else needs to be coded other than the MMI if you are just wanting to add a video input without fitting the full TV tuner etc....
Im looking at the possibility of interrupting the video source when the car is in reverse to add a reversing camera, this wouldn't be too difficult, its just finding the time to do it!
Hope this helps.