Unraveling the Dock defaults mystery

I have been working on a script that creates user accounts on the first boot of an instaDMG created OS image. One of my remaining challenges is getting the dock items setup properly. I need to match the defaults that apple uses and set them programatically instead of dumping premade preferences into the user home directory. The simplest example is on the server version of the OS the server admin tools are added to the dock. I have also seen some iMovie and other ilife items showing in the dock when they are not installed. Does anybody know how apple does this when their setup app creates the users? I expect that they have some tool or script that takes care of this when users are created or at first logon. Thanks, Blake