Under an older version of ZLM we were able to copy the Agent CD contents onto an NFS share and created a script we ran with the '-a' agent only switch and also something like '-s' (cant remember) that used a response type .txt file.

What is the best method for a silent unattended install to existing servers?

The method we were using does not seem to work with 72IR2 as copying the CD .iso to disk skips many hard links in the iso and the agent install has an error.