The cartoons that sometimes illustrate the various use scenarios don't show wireless connections at the secondary network. But surely the AP scenario is intended to work that way!?!
I'll see what happens when I get a chance to flash the new firmware on the Buffalo box, and with the new gizmos. Maybe it's all user error, but if so I'd like to see someone do it with the instructions and software I have. (Yesterday I even tried the "wizard" interface again - still no go.)