libvirt users - Aug 2014 - virtio hotplug in CentOS 5.10 guest incomplete

Hi,
I just tried to hot-plug a virtio disk to a CentOS 5.10 guest that runs
on a CentOS 6.5 host. The Problem is that while the device shows up
under /sys/ the corresponding device node does not:

/sys/devices/virtio-pci/virtio0:
bus  device  driver  modalias  net:eth0  power	status	subsystem  uevent
 vendor

/sys/devices/virtio-pci/virtio1:
block:vda  bus	device	driver	modalias  power  serial  status  subsystem
 uevent  vendor

/sys/devices/virtio-pci/virtio2:
bus  device  driver  modalias  power  status  subsystem  uevent  vendor

So virtio0 is eth0 and virt1 is vda but virtio2 has no device associated
with it.
Any ideas why the system doesn't pick up the device all the way?

Regards,
  Dennis