Provisioning, Xen and Storage

I'm very slowly making progress, but reached a new impasse.

I finally got foreman talking to Xen via libvirt. Figured out the storage
pool definitions and can now create a host. However, it fails to properly
instantiate the guest due to the following error:

"Failed to create a compute test (Libvirt) instance Call to
virNetworkCreateXML failed: XML description for unknown volume format type
raw is not well formed or invalid "

I've tried both raw and qcow2 (my only two options). I'm trying this as
xen not KVM. My ultimate goal is Citrix, but i'm still working on getting
libxenserver/libvirt compiled and cooperating. Until then I"m trying to
get a "supported" config working.

Any thoughts would be appreciated. Does anyone have a transcript or howto
they used to get provisioning to Xen working (preferable not KVM)