I had an "Agri-Fab" tow behind broadcast spreader. It ended up out at the curb with the trash after one season. The mechanism corroded so badly that the drive wheels locked up. I figured it was a fluke so when I wanted a tow behind lawn sweeper/catcher I found an "Agri-Fab" unit I thought looked pretty good. Bought it. It lasted less than one season before it went to the dump.
So my experience is, do not buy an Agri-Fab brand anything.
As for a tow hitch, you might be able to buy a heavy duty EYE BOLT (stainless or zinc plated to prevent rust), something like a 3/8" size and some lock nuts and a couple washers. Then simply drill a 3/8" hole somewhere on the back of the ZForce unit and install the eye bolt. There are lots of different qualities of hardware, I would strongly suggest heavy zinc plating or stainless steel. It might cost a couple bucks instead of 50-cents, but it will last forever. Also, when you drill the hole, make sure to spray in some automotive primer over the newly exposed bare metal and then touch it up with some Cub Cadet yellow paint to prevent any rust from starting at the hole. 5 extra minutes, and $3.50 worth of paint, will prevent a ton of problems a few years from now.