Attempting to disable Check for Updates Automatically does not persist the values upon closing the Control Panel Applet. This occurs under Vista only, this does not happen on XP.
java version "1.6.0_10-rc2"
Java(TM) SE Runtime Environment (build 1.6.0_10-rc2-b31)
Java HotSpot(TM) Client VM (build 11.0-b15, mixed mode, sharing)
Microsoft Windows [Version 6.0.6001]