The order line number of the product, set by the buyer
invoic_Examples
<documentReference documentType="BuyerOrder" id="555666" date="2015-10-01" lineNo="1"> invoic_XPATH
/b24Message/invoice/item/documentReference[@documentType="BuyerOrder"]/@lineNo
invoic_Required
No
invoic_Type
Number
invoic_Sort
18000