libvirt-0.7.7.2.fc13 fixes 2 important bugs:

• Fix USB devices by product with security enabled (bz 574136)
• Set kernel/initrd in security driver, fixes some URL installs (bz 566425)

The latter is a beta blocker.

Unfortunately this is also a libvirt version bump from what is currently queued for f13 (0.7.6 vs. 0.7.7). The latest libvirt release was inadvertently committed to the f-13 branch, but intended only for updates-testing. Not sure if there is any way around this.