I have a Honda Ridgline and I installed my own camera and yes, made it work while in drive. Why? Mainly just to see if I could. The novelty of looking at the world in reverse quickly wore off, so I rarely switch it on. While I was at it, I added a second video input that allowed me to send my iPhone screen to the nav screen (or any other video source, though I wouldn't recommend playing a movie). A switch lets me choose which video signal I want. So I have a small box with two switches. One switch activates the video input while in drive, and the other switch selects the videos source (rear camera or iPhone).
My wife's Element is a lower end model, so I don't know what's comes with other Elements, but if they have the same kind of nav computer my Ridgeline does I imagine this woudl work the same.
Just to get a rear camera working under normal circumstances, I had to get the video signal into the nav computer. There's an input there ready to use, so I just had to build a plug for it. On the Ridgeline forum I found instructions on this and it was a breeze. So I plug the cameria video output into this new plug and connect it to the nav. I get electricty for the camera from the rear power outlet, splicing into the wires. This means my camera is always getting power when the truck is running, but it's been working fine for more than a year now.
So that's the normal setup. When I put my truck in reverse, the nav computer switches over to the camera (which is a license plate mounted camera -- not body drilling for me). When I go into drive, the screen switches back to the nav screen.
The trick to making it work in drive is tricking the nav computer into thinking the car is in reverse. There's a green wire on the nav that gets this signal (which comes from the taillights). Of course, I don't want this signal to be always on, since then my nav computer/radio would never work. So I built a little box with a switch that lets me turn it on and off. I jacked into the same rear power outlet and ran that into the nav's green wire (switch in the middle). I added a diode as well, to prevent the electrity from running the other way up the green wire and possibly turning on my taillights while in drive.
I think I've explained this horribly, so maybe the diagram I drew will make more sense. Feel free to email me at Scott (at) Skaught.com if I can shed any more light.