How to apply SP3 to server copy of SLSS 8.0

Hi, I've got CDs for SuSE Linux Standard Server 8.0, and SP3 CDs for the same. I have an autoyast server configured with the contents of the CDs on an NFS export, but I want to update the RPMs etc. to SP3. How do I do this? Is it just a case of copying the SP3 CDs contents over my server dir? Or does the SP3 CD completely replace in its entirety the original CDs? Tom PS. incidently, has anyone else been unable to get grub to correctly probe the disks on a HP Compaq DL360 G2? It just doesn't find any disks, and grub is completely fscked up so it won't boot. RedHat ES 3.0 works fine...