If you look at the console on your own machine, you'll see that 'AutoUpdate' does not have '(managed)' in front of it. that's because it isn't actually managed from ePO - It's built-in to each local installation of VirusScan.

It's time can be changed by the local user, but there's a better way if you want to manage when updates occur from ePO....

Within the User Interface policies is a checkbox: 'Disable default Autoupdate task schedule'. if you check this box, when policies are applied, the local AutoUpdate task is disabled (it can't be removed from the list). However you must also setup your own update tasks, and schedule them.

(I suggest you do this first and make sure they are working before disabling the default AutoUpdate)

You can have greater control this way, so that (for example) you can check for DAT updates each hour, Engine updates (via a seperate task) each day, patches once a week and so on....

hope that helps.