Your solution may be for an electrical connections trailer relay isolation with universal harness.
http://www.electricalconnection.com/wire-harnesses/hrns-trailer.htmThis will cure your power draw issue as it uses relays to light the trailer bulbs, isolating your motorycle electronics.
I have one on my car and motorcycle. If you need to go to a 4 plug trailer, they also sell an adapter that clicks in place.
Is this more what your looking for? If so let me know if you need wiring help.