I have the camera directly powered by the reverse light (no errors via the LCM) and as soon as the reverse camera input on the Dynavin senses the video signal the display changes to the camera. The camera I'm using is a small unit that mounts in one of the number plate light fittings, it comes with a bright white LED to replace the illumination of the incandescent lamp that gets removed.
Routing the cable was a bit of a mission, but with the skins off the tailgate you unplug the the left handside rubber cable duct next to the top hinge, take off the left rear skins in the luggage area, pull off the tailgate/door seal near the left rear head lining. Using a straightened metal coat hanger or cycle brake cable outer sheath, feed the cable down the LHS tailgate to the openning where the rubber cable duct fits in. Then feed it through the rubber cable duct, with the headlining slight loose with the rear seal off you can easily grab the cable from the metal hanger or cable sheath. Routing from there is relatively easy down behind the left hand side luggage area covers, out the rubber gland behind the LHS rear seat fixed swab and under the door well kick plates to the front of the car. Sorry I don't have any pictures from when I did mine.