I'm trying to set up a scheduled task which will work under the Network Administrators account, whether the account is logged in or not (on a specificed computer)

According to the Task Scheduler, I need 'Logon as batch job rights'.

Attempting to change this setting in the Local Security Policy window has it the option to add the Administrator account to the groups greyed out. Currently, only LOCAL_SERVICE may Logon as Batch job. Attempting to add administrator to this group hasn't worked. How do I make it able to set this permission so that I can run tasks if I'm logged in or not?