I know I read about this but I cannot find it again. I think it may have been in the documentation pdf from the rdp iso. Basically you get .lic files though and you can just add them to your existing ones using the Altiris Licensing Utility. It doesn't appear to make a differentiation of Altiris Server licenses vs RDP server licenses.
What it really comes down to if you aren't comfortable doing unattended OS installs then use RDP. However if you don't mind setting it up, there is nothing to it for Windows 2008 SOSI. 2003 is a little more involved but not bad. They even detail it some in the KB
How To Create A Localized Windows 2008 Scripted Install Job
The licensing in general with the DS is such a pain I didn't bother trying to get RDP involved as well. I just made the job on my own. The real gold of the whole process is in the ProLiant Support Packs.
HP ProLiant Support Pack*-* Download drivers and software - HP Business Support Center
After the scripted install is complete just run hpsum.exe -silent -force from the latest PSP and capture codes 1 and 3 as success.
