we sell both vat and no-vat items. 95% of our products,in the past we only sold non vat items. customer's are set up as non vat. we now sell vat items as well. the vat setup in the inventory is set to default as vat item for certain items but when invoicing it defaults to non vat. how do we change it to pick up the default vat from the inventory setup and not the customer setup?