RE: [otrs] Time Accounting

Does anyone know how to fill the time_unit text entry field with a default value? I'll be setting the field to be mandatory soon and it would be a real pain in the neck if you had to click in the field every time (even if closing a ticket just after you replied or the like). I'd just like it to default to zero and the agent can change it if it's a billable action (closing a ticket in and of itself doesn't really take up enough time to count as a billable item) Any help would be great! Thanks! Love OTRS! - Pete McDonnell