Problems registering a Full Virtualized virtual machine

Hello,

I'm trying to register in RHN a Full Virtualized Xen DomU.
I can register it following the procedure in:
http://kbase.redhat.com/faq/docs/DOC-9933

But it doesn't appear as a Virtual System in Systems -> Virtual
Systems in RHN. It's register as a Dom0 instead of a DomU.

It happens with one of two DomUs. I don't know what is the difference
between them.

I checked files in /etc/sysconfig/rhn/virt and everything seem to be ok.

Where else could I check?

The Dom0 and DomUs are RHEL5.3.

Any help will be welcome.

Thanks in advance