Hello,
I Installed 5.4 on a test system to use KVM, but i didn't find the "virtio-win" package with the Windows drivers.

->
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Virtualization_Guide/chap-Virtualization-KVM_Para_virtualized_Drivers.html

Is this a CentOS or Upstream Problem?

Regards,
Sebastian