Backup Camera Wiring + Reverse Trigger

Hi everyone, My wife drives a 2006 Kia Sedona LX minivan and I wanted to install a backup camera to make it easier for her to park. My setup is as follows: Rockville RVD7.0 Headunit http://www.amazon.com/Rockville-RVD7-0-Double-Receiver-Bluetooth/dp/B00U1WEALC/ref=sr_1_1?s=car&ie=UTF8&qid=1457208736&sr=8-1&keywords=rockville+rvd7 TopTier Pro Backup Camera http://www.amazon.com/gp/product/B018800TR2?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01 BW Wireless transmitter for the Backup Camera http://www.amazon.com/gp/product/B008Z9E4DW?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01 Obviously, it's a budget setup... I wired the camera and the wireless transmitter to my driver's side tail lamp reverse bulb. I've confirmed that the wireless transmitter only gets power when I put the van in reverse. On the back of the radio, I have a Reverse trigger wire, along with a Parking Brake wire and a Yellow female cable for the Camera video input. If I wire the Red +ive from the wireless Receiver to the Reverse trigger wire, the Ground to Ground and the Parking brake wire to Ground as well, I get no power to the wireless Receiver and cannot select the Camera input on the headunit. Now, if I wire the +ive off the wireless Receiver & the Reverse trigger to the RED ACC+ wire on the aftermarket harness, I get power to the wireless Receiver, the Headunit immediately switches to Camera, but does not get a video signal UNTIL I put the van in Reverse(which is what I want). The issue is....when I wire the Reverse trigger into the ACC+ on the aftermarket harness(along with the +ive wire from the wireless Receiver), the radio gets stuck on the Camera input and cannot be changed out(constant power/constant trigger, I guess?). How do I go about wiring this setup properly so that the radio switches to the Camera input, only when I put the van in Reverse. Is the Parking brake the reason? Did I do something wrong? I greatly appreciate your time and suggestions!2007 Kia Spectra EX 5MT Sedan

2006 Kia Sedona LX

Reverse trigger needs to only see 12V when the vehicle is in reverse. It needs to be connected to the reverse trigger wire of the vehicle.

Yes, you need to put the reverse trigger wire from the radio on the reverse circuit. Checking my usual source for diagrams I saw a few different possible locations for the reverse circuit in the passenger cabin, none of which I think would be especially easy for you to find. If you're decent at pulling trim, it may be easier to just run a trigger wire from the rear. Doing that, you'll be able to run an RCA cable as well, which will give you much better, more consistent results than your wireless set-up. If you end up hitting the reverse circuit in the front area, you'll a have a camera, transmitter, and a receiver as well as your backup lights all on a circuit designed for just a couple of lights. You'll want to relay that from a good switched circuit. Really I think it'd be better just to go ahead and run the wires.