Registering guests of ESX 3.5

I'm trying to determine the process of registering our ESX 3.5 hosts with
RHN so that we can register the individual guests using up2date --register
and have them appear under the "Virtual Systems" category. However, I'm not
seeing the forest for the trees as I can't work out how to go about this.
The RHN knowledgebase gives some steps (DOC-9933) but the all-important one
- registering the host - is simply given as:

1. The host system (dom0) must be register with Red Hat Network. Follow
standard procedures to register this system with RHN.

This is the step I need help with.

Thanks... Neale