Packages won’t install into /System/Library/User Template?

I'm at a new job (yah!) and working on a project introducing Mac into the environment. Initially, I'm working on a core boot image via instaDMG so there is a uniform starting place on new machines coming into the environment. One of the things I'm challenged with is AD integration. That in itself is no issue to me. What I'm trying to do right now though, is add a default login item of Keychain Minder to my instaDMG image. I used PackageMaker to build a package to deploy Keychain Minder, and then I figured I'd add the loginitems.plist to /System/Library/User Template/English.lproj/Library/Preferences/ so any new user account automatically had Keychain Minder as a login item, to assist with the messy password expiration rules. I created a default loginitem.plist with nothing but Keychain Minder (in a new account with no litter), took said file and built a package around it. Made sure it had correct permissions (root:wheel, -rw-------) in the package, build the package, but I can't easily test it - as you need root access, not just administrative, to put things in /System/Library/User Template/ - so I did the bold thing and just added my package to the instaDMG build. Only problem is, it doesn't deploy where it's supposed to - in fact I'm not sure it deploys at all. Any ideas how to test this, or where I should look for the file? I've double checked my package, and it's definitely going to the correct place... Thanks!