Sloane offer a bowser for R22 and R44, and therefore I assume that they must be aware of the regs for selling and opperating them.
My understanding is that the regs are stricter for Avgas than Jet A-1 as avgas is such a horrible substance but beyond that I can't help.
Here's the link to sloanes unit:
http://www.sloanehelicopters.com/accessor.htm
Hope this helps
CRAN