[fedora-virt] No networking?

I'm on fedora 17 and I just started trying to install a fedora 17 virtual machine where I can screw around with stuff without blowing up my actual machine. I get to step 5 of 5 in the New VM wizard of virt manager and it tells me "No networking" and has a little warning triangle icon. Whyfor? All my existing virtual machines use one of the two bridge devices I have, but it doesn't seem to see the bridges? It used to see them in earlier versions of virt-manager. Is this a bug or some kind of new feature that requires me to go to infinite pains to make virt-manager aware of the bridges for my convenience? I'll try to do the install and manually tweak the xml later to see if I can add the bridge...