Hi Guy, you may have the same problem I had with the wireless streaming box.
For some reason the video input craps out, for unknown reasons but if you have a video input live while the av1 or two is selected then open the settings menu and select pal/secam or whatever it says and the video feed will start working again.
Its a tad annoying and TBH if you had to do all that faff to get a reverse picture up i think you would quickly tire of it.
As an alternative to the xcar link how about this
http://car-solutions.com/en/car-vide...en-support.php