Reference Elements with Output Location

The ShipService WSDL includes these CustomerReference/CustomerReferenceType options:

Value Prints
BILL_OF_LADING Shipping label and invoice.
CUSTOMER_REFERENCE Shipping label, ground shipping reports, and in the Customer Reference element on the invoice.
INVOICE_NUMBER Shipping label and invoice.
P_O_NUMBER Shipping label and invoice.
SHIPMENT_INTEGRITY Invoice.
STORE_NUMBER Shipping label and invoice.