Didn't forget about this but I travel for work. Actually away from my purty now. The bike I mean. =(
I have a lot to do when I get home, including dual low beam cable and new Shad top rack and 40L case! I'll hopefully do this as well and report back. Thanks for the informative posts!
I made my own extension for about $3-5. I went to home depot and bought 1 foot of plastic covered cable, I think 1/4 inch thick, but I do not remember perfectly. Then looped each end and held it in place with the cable connectors that you hammer shut. Then I threaded the cable through the helmets' D rings and then with the 2 loops locked them to the factory helmet clip. Just a cheap option.
I seen other bikes with helmet locks and wanted one... then thought I'd probably never leave my helmet on the bike (helmet lock or not) if the bike was out of my view. Maybe I am just thinking the worst about people, but as far as I am guessing then a thief usually brings a few tools along... quite easy to just cut a thin metal cable (or the strap of the helmet for that matter).
I'd be crying if my white S1 Pro went missing!