So, I'm feeling pretty darn silly. The short-of-it is that you can tighten the clamp so that it will not rotate and you simply do it by screwing the handle around. I was trying to do it quickly, without putting my bike on the stand. I just needed the extra weight of the bike to hold the clamp in place ... I wasn't able to hold the clamp in place while I was testing it.

Anyway, it works. Thanks to all for suggestions.