Yes, that's exactly what I meant.
And you're right, I've looked all over and haven't found any way to customize the guest network outside of the options in the screen shot.
Too bad, it's a nice feature, but it basically just gives you the option of name/password. No way to specify type of encryption, visibility and other little things that would be nice to have control over.
I'll keep my fingers crossed that a future update will address this. Apple seems to add new features to the AirPort Utility all the time, so maybe it's not so far fetched...