The concept was to install an aluminum strap using the holes I had drilled in my Volae carbon seat to mount the HP Velotech headrest.  The strap is 1" wide by 1/8" thick by ~10" long and was cut from a 36" piece purchased at Home Depot.  I marked and drilled the lower hole centered 1" in from the end of the strap, then did the initial bend on my vice to clear the edge of the seat.  I disassembled the headrest and marked the second hole location on the strap using a Sharpie marker, then drilled the second  hole. 

The second bend was "eyeballed" using the vice and adjusted by trial and error to be about right.  Pic 1 shows the result.  I used #10 by 32 tpi flat head machine bolts with rubber gasketed washers on both sides and nylok nuts to hold it together.  I did have to buy 1" bolts to accomodate the strap and get reasonable engagement of the nuts on the bolts.

I had already mounted "fuzzy" (hook) side Velcro on the Eternalight (supplied by Wildfire in Maine).  My previous attempt to mount the light on my large Eurobag failed, leaving unsightly urethane deposits.  Sigh!  I cleaned the strap surface and mounted loop side Velcro on the strap (pic 2).  The assembly looks good (pic 3), although I'll probably rubber-band the light in place for insurance on my first few rides.

The first shot is Lock 55 on the historic C&O canal, and was taken west of Hancock, Maryland. The path in the back leads up to the paved WMRT.

This pic was taken by two folding bike riders from Portland, Oregon.  It was a big Oregon and Arizona day, with folks from out west "thronging" the trail!

I'm working on a rear light mount for my Volae - hopefully that will be the next posting up!