Managing iChat with MCX

1) The first iChat key variable "%@@<ichat_server>" doesn't work. When a user launches iChat, they are told that "User %@" doesn't exist. For some reason the variable is being taken literally by iChat.app, and not using the "%@" to represent the user who is currently logged-in's short name as described by Apple. 

2) Even though I have the iChat policy set to me managed once (rather than "often" or "always", users still cant edit or modify the iChat settings. My goal is to push out a basic setup via MCX, but still allow users to modify their settings as needed manually. I assumed that by setting the policy to "once" that it would allow users to modify the iChat config, but all settings are greyed-out and a mesage appears in iChat's Accounts pane that says something like "These settings are being managed by your administrator."

I have an internal XMPP (Jabber) serer that will provide text and video chat for internal Mac users. Id love to be able to push out a policy that has all my Mac users iChat preferences pre-configured and centrally managed.

-Dan