7.3 - vtws_retrieve, vtws_update, vtws_revise remove LineItems from an Inventory record

Have created a new Scheduler Task (cron_task ) which needs to update an existing SalesOrder record, so I was using vtws_retrieve, to retrieve the SalesOrder then change the required fields, then calling vtws_update and passing the edited SalesOrder.

Doing this removes ALL LineItems from the SalesOrder.

So I switched to using vtws_revise to achieve the same thing, and only passed the edited fields (along with id, and hdnTaxType - to get around #1561 (closed) ) but this also removes ALL LineItems from the SalesOrder (and changes all Totals to 0)