Chickens, eggs, add-on images, and ZFD agent

I've taken on the task of revamping our imaging process (yes, lucky me!).

What I'd like to end up with:

1 A new computer is unboxed and plugged in to a special VLAN in our help
desk area). Based on the VLAN IP address, a scripted image is pushed
down to the computer when it's fired up. No problem.
2 Part of the scripted image prompts the tech to name the new computer.
This part's done.
3 The scripted image is, of course, a few images: base OS, add-on images
for apps, etc. I've got these ready to go.
4 The computer reboots after being imaged, is joined to our domain using
the name from step 2 (using M$ sysprep voodoo that I haven't gotten
working yet).
5 The tech logs in using a special "setup" account; all the add-on
images from step 3 get installed. This is what I'm having problems with.

Someone posted a message recently having to do with step 5, something
about having the ZFD agent installed but not registered (?)... but of
course I can't find it. If someone would be kind enough to point me in
the right direction, I'd be very grateful.

And of course I'd be happy to hear any suggestions from others that have
been down this road before. We're running a Windows-only network.

John