I doubt it......the 12v sockets will charge your phone and camera when the bike is running. So I'm assuming that they are on a circuit linked to the alternator, which is where the power comes from.
I know I looked at my battery minder when I first got the bike and it's wired directly into the battery circuit.
Of course you could specifically rewire one of them to do what you want but then you will be short an external power outlet!!
That doesn't seem right Aussie. I read that the 12v power outlets are powered at all times, but that the battery has built in protection and will shut them down if voltage drops below 11.2 or something. They are powered off the battery. Charging through the powerlet should work.