Just got the car back from Sound-in-Motion in Allston, Ma (Sound In Motion - Boston's Best Mobile Entertainment Design, Installation & Custom Fabrication Shops). I had them wire up the Nav-TV module (RGB emulator) and an Eclipse BEC-106 reverse camera.

When the car goes into reverse, the backup camera automatically switches on... turns off when the car shifts out of reverse...

Eclipse reverse camera:
Amazon.com: Eclipse BEC106 Back-Eye Vehicle Rear-View Camera: Electronics



NavTV BMWV+ switching module:
NAV-TV Corporation: BMWV+ Video and Backup Camera Aux Input for BMW




And some pics of everything installed...