The Altiris process is designed to both sysprep an image (to make the OS unique on the network) AND strip the GUID from the agent (to make the agent unique in the console). It's a combined task and hence called Prepare For Image Capture instead of "run Sysprep" or something.
The sysprep file used in the capture is largely irrelevant if you think about it - the captured system doesn't much matter.
The sysprep file used in the image deploy attempts to make things easy on you. Anyone who has done it manually knows that you need to walk thorugh the WAIK with MS to configure a custom Unattend file. K. With Altiris/SMP, there's no need for a custom unattend file 95% of the time, saving customers time and energy. Confusing? Only to those who are accustomed to doing it the hard way. :D
As for the off-site deployment, that all depends for what you want to do.
1) if the off-site location has NO connectivity to Altiris EVER, then you don't want to distribute an image that will try to connect. That's a bit like putting in an unattend file to join a domain when there's no AD server to connect to. makes no sense.
2) if the Off-site location has limited connectivity, then go ahead and deliver the image captured with our product.
Now, if after looking at those questions, you still want to use Altiris to capture the image, you can - uh - sorta do that, but you're not saving much time over doing so manually. You'd have to essentially build an image without our client in it, sysprep it manually, boot to PE manually (PXE or whatever), and capture the image with Ghost, and distribute that to the remote location to be imaged manually again with Ghost.
Not ideal, but not too far from what you did manually with MS (minus with SCCM, I think).
Sooo, if you have a few more details, we could probably clear that up. :D