I have one I never used, it bolts to the footboard bolts on the bottom & upper motor mount bolts on the top. If interested in buying cheap, I can send you some pics.
I just sent you an email request for a pic of your trailer hitch. From the pic in your forum garage of The Green Hornet's rear view, the ball looks low and close to the fender. Rodie's pic with his Black Magic bike and trailer combo makes the ball look much higher?