So the above pictures show my Pioneer NAV system and Rear camera setup. In pic #5 you can see the black mic for the voice command capabilities of the NAV system. I can use the NAV in a location that is great (also for the camera view). You can switch back and forth from NAV to rear camera (rear camera is automatic when in reverse). I can listen to my 6-CD stock unit at the same time. I think this is still a better approach than the 2004 NAV/CD system.
"It's what you learn, after you know it all, that counts - John Wooden