Here's my write up on camera install on the limited hatchback.
The installation was partly done by an installer, so I don't have all the steps. I'll show what I can and make best guess of the missingap steps.
The camera that I got was from ebay. It's easy to find the same one by searching for "E366 camera". Buy from a reputable US seller so that if something goes wrong with the camera you can get have it exchanged easier.
This camera may have issues with water proofing, so I covered all the seams, around the mounting post, around the gap between wire and post with shoe goo for water proofing. Clear silicon probably works better, but that's just what I had that can water proof.
Let's start the install from the HU. It's a good idea to test the camera to make sure the camera works with the HU before spending all the time mounting and routing wires.
To get access to the HU, use a smooth butter knife to pry the cover off. Start at the top left corner. Use your nail to get create a slight gap by pulling the cover towards you. Insert the butter knife in the top left corner. Use gentle rocking/prying action to create more gap. You only need about 1/4 inch gap to get the cover loose. Work your way across the top. Once the top is free, nudge along the sides, then the bottom to get the whole cover loose. The cover is attached by hazard light, and the wire harness for the A/C.
Squeeze on the center top tab on the harness to detached it from the cover. Lift the cover and push it out of the way.
Take out the 4 screws holding HU, pull out the HU. You don't need to disconnect any of the wires.
Hook up the adaptor harness from SVXDC to get the RCA video jack.
Unscrew one of the screws on the HU chasis and then attache the ground wire from the adaptor harness to the the chasis.
Hook up the RCA cable from the camera to the jack.
Hook up your camera and do a test with ignition on and shifter in reverse. You should be able to display image from your camera on the HU display.
Put the HU back.