Wireless Backup Cam - Auto On?

I installed a wireless backup camera from Costco on my '04 last month. It works as advertised, but the one issue is that I have to push the power button on the screen to turn it on. The camera in back comes on with the brake lights. I would like the monitor to power up with the accessory power it gets when the car is turned on. I assume it would involve some kind of modification of the monitor/receiver electronics. Anyone knowledgeable about this kind of mod?