Get a Powerlet socket, appropriate bracket (an "L" bracket mounted off the rear passenger peg hanger where it attaches to the subframe, with the socket in the top of the hanger's "v" would be clean) and an SAE to Powerlet adapter and simply charge through the Powerlet port wired to the battery. And obviously, the socket is useful for more than just charging.
Eastern Beaver is a good source for all the parts you'd need.
Here's how I have one mounted on my Tuono, which is damned near invisible if you're not looking for it and I suspect that having yours "inside" the footpeg hanger would be even less obtrusive
