Mine's 09 too. That was a bummer to see the comments on that feature. However, I believe the reason that feature doesn't work on the 07-2011 vehicles is the head unit, not an engineering limitation. When I order mine I'm going to let them know I'm running a 2014 Navi and 2012 OnStar VCIM.
After 2012 and early 2011 the Navi and OnStar VCIM were upgraded to pass data (Navi Coordinates) from the O/S VCIM via the K Line/CAN BUS to the Navi head unit. This pathway is likely commands the back up camera on later model trucks.
There's even a remote possibility that just a swap to a 2012 VCIM would do the trick in triggering the back up camera via the turn signal. GM held back a lot of features and options to convince buyers to sell/trade and buy a later model truck.
My wifes 07 Beetle Convertible had an aftermarket OBD dongle plug/program that allows all four windows to roll up/down with the factory remote and defaults to rolls up all the windows when the it's locked. It can also be canceled with the remote. After getting your brains blasted out on the highway with the top down it's easy to pull switch the top up and walk away with all the windows open and leave a phone or wallet in the console. It's paid for itself 25 fold. It's weird to walk away from the car and hear all the windows rolling up knowing you forgot to do it.
That key fob control of the windows feature is awesome for black trucks with auto start. It means Mom can start the truck, A/C blasts to full and you can roll all the windows down to evacuate all the hot air trapped inside. By the time the kids school stuff or groceries and stuffed in back, the kids can be put in the car seats with the windows down. In the end, most of the supercharged hot air is out of the truck from circulation and rolling up all the windows when driving away yields only cool air the a/c never had to overcome.