Yeah, I am just now figuring that out. :/
Fortunately I think I can work with that limitation. I need 2 zones because my projector can be aligned to point at 2 surfaces. One is the main screen with a 7.1 array. The other is a smaller area behind the bar, where there are stereo speakers--but I will only ever need to play the FL/FR signals from the 7.1 system there. Therefore, I should be able to connect the pre-amp outputs for FL/FR to a set of analog inputs, and drive zone 2.
If for some reason that doesn't work out I'll have to add an auxiliary amp I guess, but per the 818 thread this trick should work for copying the main sound to a second pair of speakers.
Anyway, now to find a good price on an Audyssey XT32-equipped unit with powered Zone 2... I just missed all the 818 deals.