What to do? Why, put on on there myself.
I spent a few hours this weekend and produced this:
I used a couple of 10' PVC pipes. They were 1 inch, high pressure pipes for sturdiness. To mount the hanger on the cart, I cut the 'T' fittings into half circles and fastened them to the cart handles with band clamps. The handles are not round which gives unexpected stability once the band clamps where tightened. I thought I might have to put cross members on it to keep it from lurching; but it is very solid.
Total cost: about 4 hours of time (including shopping and cleanup) + $27 in material.