REVERSE CAMERA

Hi guys needed some advice from a genius on how to hock up a reverse camera to my system I want to use the standard screen built in (RNS 315 touch-screen navigation). I know there is an option extra where the reverse camera pop out of the VW badge. I wanted to buy simple camera online and to mount it by the number plate and connect it to the loom? (question is where) and it should display the image on the standard screen when put into reverse? As these cars do have the option extra would my method work if so how?

You help would be greatly appricated.

the car im talking about is a Passat cc tdi 170 DSG 2009