I have a machine that I use as a Media Center but in order to use an XBox as an extender I have found I have to keep it off the domain: it just won't connect, so to manage it's updates I have changed the WSUS server location:
- Run “gpedit.msc”
- Go to Computer Configuration; Administrative Templates; Windows Components; Windows Update.
- Change the setting for “Specify intranet Microsoft update service location“ to your WSUS server.
You should check the Updates are set to install automatically and "Give me recommended updates the same way" to ensure the updates are installed.