Did U-Haul install a hitch that you purchased online? It looks like U-Haul sells basically the same hitch as the Hidden Hitch for about $40 more than online. Their installation price seems reasonable - about $50. I called several mechanics, and nobody seems interested in installing a hitch.
I also thought about buying some of the "Curt Trailer Hitch Support Straps" to help stabilize a bike rack, but I'm worried they'd damage the plastic spoiler on the Sport hatch.