[Fedora-xen] No pcifront in F10?

I have a virtual machine landscape consisting of a CentOS 5.3 Dom0 with Xen 3.1.2, some PV CentOS DomU's with PCI passthrough (same versions), and I'm trying to implement a F10 DomU with PCI passthrough. I set everything up for the passthrough, and the F10 guest can't see any of the devices with lspci. If I boot a CentOS PV machine with the same PCI passthrough configuration, the devices show up with lspci. I've seen some posts in various places about this issue, but no solutions. How do I implement this?