First posted on Serverfault: I am managing 20 or so Apple computers running 10.6.4 with a Mac Mini Snow Leopard Server (also 10.6.4). I am using the built-in OpenDirectory in addition to Kerberos to bind the clients to the server. Users have networked homefolders (stored on the server) that they can access by logging into any of the computers (much like a lab environment). Using the Workgroup Manager utility I have been applying Managed Preferences to the machines. Many of the preferences work, I can get the dock on the left, auto-create the logged in user's iChat account and auth via Kerberos, etc. However, it has been increasingly apparent that many of the settings just do not work. None of the settings under Media Access not work at all, though mcxquery shows them as being enabled. Additionally, Bluetooth disabling, auto-importing iCal accounts, and providing a predefined set of Safari bookmarks all do not take effect even though, as before, mcxquery shows what I would expect to see with the settings enabled. I've stumbled over a number of forum posts with problems similar to what I am experiencing, all without resolution. Any insight is appreciated.
Create the correct plist settings on a local machine and test to see if they work there. Once you know the plist file is ok import it into workgroup manager and see it that makes a difference.