2006 touareg oem back up cam

I have a 2006 VW Touareg with the Factory Navigation System and Back-up cam. I would like to replace the factory Nav unit with a aftermarket one and would like to retain the factory back-up cam if possible. So my question is does anyone know of a integration piece that I can add to retain the oem back-up cam or is there a way I can hardwire it to a video rca and plug it directly into the aftermarket nav head unit?I drink current, eat ohms, and bleed voltage

I have done this on several vehicles.  Never a VW, remove the camera and see if there is a plug at the camera.  There are usually only 3 connections on the camera.  Power, ground and video.  The video has always been in a shielded cable.  The shield and the ground connection are the same.  

All of these wires are behind the deck as well.  I just do not know if it will be in an easy to identify harness, or mixed in with the rest of the wiring.