Earlier, Stewart Kissel wrote:

...Our mechanic has just encountered this
situation, specifically a US registered Pawnee
that has not towed before. He has been told
he needs a STC. Has anyone come up with
a work-around for this?

Air Sailing has recently managed to certify their Pawnee
for towing, and indeed it wasn't easy. You might contact
Jim Hayes of Air Sailing for some guidance.

Bob K.