I tow my Scamp
with a Ford Ranger pickup that has a hitch on the front and carry my bike in front.
However, I also have a welded up mount that slips over the hitch on the back, in front of the ball. There is a short piece of vertical square tube welded to the top of the part that fits around the hitch. Another section of square tube slips over the short vertical stub and a bike rack is welded to that. A hole drilled through them has a bolt or pin so it does not jump off.
I might suggest a 1 1/2 inch long piece of square tube of the size that will slip over the attachment that holds the ball of your hitch, and weld the bike rack to that. Then you can easily remove it when not needed.
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I will reply with pictures.