I've had a quick look into this and i'm fortunate to have a Bentley manual as it gives you a wiring diagram. There is a control unit that resides in the tailgate that activates when you press the button. I'd hazard a guess that it would be simple enough to mount some sort of solenoid in the tailgate to mimic the control unit to pop the lock. Although a nice little touch from in the vehicle to just 'pop' the boot, it almost seems pointless TBH as you still have to physically lift the tailgate open. I'd consider it if I had the parts to do it.