My understanding is that even if you have the software upgrade (WHITE NAV DVD 4.3x upwards) the 2005 RL is missing the wiring harness/switch that connects/triggers the camera on when put into reverse.
In the Acurazine forum, a poster named Qatar tried to have the 2006 switch retrofitted, and was unsuccessful for reasons I cannot recall.
In order to install a camera, my understanding is that you can use an aftermarket set up, such as the TVandNav2Go products
http://www.tvandnav2go.com/acura-tv-navigation.html
to act as the interface/switch. Using that same product or a variant of it, you should also be able to play DVDs on the nav screen.
A stero shop should be able to do the integration, because that unit only takes care of video, and you would need something to also take care of the sound. I believe you can somehow integrate the USASpec type iPod and aux in units with the video unit to get sound and an iPod connection to boot. Given enough $, you can do anything.