<xs:element name="InvoiceRefNbr" minOccurs="0" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:annotation>
    <xs:documentation>
      <p xmlns="http://Hps.Exchange.PosGateway">Card Acceptor Reference Number.</p>
      <p xmlns="http://Hps.Exchange.PosGateway">Visa: Value Added Tax invoice reference number. May contain spaces.</p>
      <p xmlns="http://Hps.Exchange.PosGateway">For Mastercard:  Card Acceptor Reference Number.</p>
    </xs:documentation>
  </xs:annotation>
  <xs:simpleType>
    <xs:restriction base="xs:string">
      <xs:pattern value="^[a-zA-Z0-9 ]*$" />
      <xs:maxLength value="25" />
    </xs:restriction>
  </xs:simpleType>
</xs:element>