Default PDF Viewer

Hi All!
I need to force all user profiles to open PDFs by default in Adobe Reader (8.12).
I cannot seem to make this stick.
I have tried adding the launchservices.plist as a package, and also editing the file on my OS package (10.4.11 PPC)
both in the local profile preferences and in the User Template.
After imaging, the plist is there, and looks correct, but I have to reset with the <change all> (which doesn't seem to change the plist text) before it will work.
Anybody have any tips?
Sandy Hinding
Lead Macintosh Technician
HelpDesk Manager
Lakeville Area Public Schools
952-232-2053