I am using a Accessory Plug and Outlet I got from Gerbing. I have heard it called a Powerlet. I think it is the same as the BMW plug. It has "Hella" molded into the plastic. I have also heard you can get something like this at from John Deere. I have my outlet connected to my heat-troller.
I really like it. I was originally using the coax adapter that came with my electric liner, but that required two hands. The accessory plug is easy to connect with one hand while riding, even when you can't see it in the dark. (don't ask how I know that) I placed the outlet at a right angle to my bike, so it unplugs easily as I walk away from the bike (doh!).
I put the outlet on the left side of bike in the abs (non painted) panel, just below the Honda wing on gas tank. I mounted my heat-troller in the same panel, but just below the handlebar. I can reach the outlet easy when I am riding and can adust the heat-troller without looking. The wire to vest runs down out of my jacket, then fwd along the break between the gas tank and frame.
Since this picture I have changed to a right angle connector. It routes the wire parallel to the tank and frame, and still pulls out from outlet easy.
matey, I thought your picture was of under my seat. My accesory wiring is very similar.
Jeff