The task is sent to JobFile as soon as the trade/supplier is assigned to the task therefore anything else added to the task (documents & POs) will also be sent through to JobFile before it is scheduled (this is at the 'unplanned' status).
The good thing about the relationship between JobFile & ClickHome is that even though the supplier won't be notified by ClickHome until the task is scheduled, when a PO is uploaded to JobFile (by ClickHome), JobFile will send an email notification to the assigned supplier (providing they have a free or paid account) letting them know a PO has been added to a task they are assigned to.
Therefore, as soon as the PO is uploaded to ClickHome the supplier will be notified and they can login to JobFile and access the documentation they require.