I've been thinking about adding an outlet as well, I've kinda been leaning towards mounting it in the shock absorber area .
If it's not too cold the in New England today, to take a look at your bike, look at the right side of the bike just behind the right shock absorber, there should be three holes in the metal plate .
I was thinking of opening up one of those holes to install the power outlet .
Where ever you do decide to mount the outlet, put a fuse in the hot wire, just as a precaution for damage to the outlet, or wiring .
There was an OEM kit available, and from the looks of the drawing, it mounted below the side covers between the frame tubes, just above the swing arm pivot bolt .