Please, I'd like to know how to do this too. I've poked around and it seems a service named ROG Gaming Key.exe was responsible for setting the power policy each time the power adapter was connected/disconnected. I'm setting it manually for now which is super annoying. I'm at the point where I'm considering uninstalling ROG Gaming Center to see if it works!
My Rig: Intel Core i7-2600 | R.O.G Maximus V GENE | Corsair Vengeance DDR3-1600 8 GB | Asus GTX 670 DirectCU II | Intel 520 Series 240 GB SSD | WD Caviar Green 1TB | Noctua NH-U12P SE2 | Enermax NAXN 82+ 850W | Silverstone TJ08-E | Dell U2312HM | Win7 HP