Per the documentation you are correct. But you can do this (I haven't
made it that far yet) by modifying the information on your boot media.

Basically you make a 'jumpstart on cd' system but instead of installing
from the cd itself the target system obtains it's profile information
from the remote location. I can see it is possible but was hoping
someone had already done the *hacking* of the /etc/rcS script in the
jumpstart system to do it.

Also, DHCP booting is only available in the more current boot proms and
I have a large array of systems (old & new) to deal with.

Some routers can be configured to forward RARP requests but this is not
standard (so not reliable).

Thanks.