Imaging at remote sites

I have a Netware OES network with some locations that are big enought to
have a file server, and many locations without a local server. I also
have a Zen 7 sp1 server at the "main" site. The remote sites are across a
fiber wan, on a "private" network, they are all on different segments of a
10.x.x.x network and are all behind the firewall.
I can manage the desktops at the remote locations fine, remote control,
inventory. I would like to use zen imaging at the remote sites. I
don't(can't) have netware server at every location to run an imaging
server. I saw a reply in a post dated Dec. 5, 2006 21:05:11 UTC from
Craig Wilson (Subj: Upgrade from Zen 3.2 to Zen7 sp1) that referred to
trick of using a desktop with a bootable cd to act as a imaging source.
Can Craig or anyone elaborate on this technique?
TIA, Rich