Hey, how did you do that?! Thanks, back alley.
Mountainsmith, I use a generic single contact hotshoe adapter with cable connector on the M8 while the SB800 is mounted off camera on a simple arm (not sure if that's the right name, basically just a strong piece of metal with a fake hotshoe on one end and a tripod hole on the other) connected to the adapter via cable. There hasn't been any problem with the firing of the flash. As for exposure, the SB800 would be on manual mode and I adjust the output as necessary. For this shot, shutter speed was at 1/45 at f/8 and flash output was I think 1/32. Hope this is useful to you.
Douglas