On the Tasks tab right click and select "schedule task", give your new task aname then select "ePolicy Orhcestrator Agent Update" Click Ok.
Next, edit the task and click settings, uncheck the Inherit box and select the updates you want ePolicy to update, as you can see you can have it just do the DAT or both the DAT and the engine and the ePolicy agent as well to name just a few.
You might also want to modify the Virus Scan User Interface properties on the policies tab for your site to disable the default autoupdate task schedule so that only the ePolicy schedule applies.