CJ, where are you located?

The signal flow diagram says that the camera unit takes the image from the camera and gets it into some kind of signal, then the AV control unit (head unit basically) converts this signal to an image on the screen when the reverse(for North America) is selected.
If your head unit is otherwise working fine, I don't see why it would be the main issue here. Maybe the computer chip that processes camera images is cooked
(computer guys, please correct me if this is not how electronics like this work) and it just outputs a blank image to the screen, but I think it's more likely that the camera module is giving a jumbled signal.
I think if you sourced a used part, I would get one from a similarly equipped model to be safe. For example I don't know if the head unit from a base model Y50 with no rear view camera would know what to do with the images coming from the camera.
Maybe it works, considering the display screen of a navigation model and one without seem to have the same part number, just haven't heard about it being done.