vt7.3 - Webservice - Inventory modules using Query & Update operation deletes all LineItems

We are using the Webservice functions query and update, to find a specific SalesOrder record, and update it. This is being done via both Webservice and server API (vtws_query & vtws_update)

When you view the response form the query (can do 'SELECT * FROM SalesOrder;') and then using the returned array, update a value in the SalesOrder record, then pass this object back into the update operation, the SalesOrder is updated but ALL LineItems on that SalesOrder are deleted, and the value of the SalesOrder is set to 0.

If you use the vtws_retrieve function to get the SalesOrder, and update it in the same way, this data object includes a 'LineItems' element that is missing from the Query operation. Updating using vtws_retrieve does not alter the LineItems (unless you edit them before the update call)