Used to log Merchant specific customer identification.
Note: For GETI check transactions, this is sent in the CUSTOM3 field.
Source
<xs:elementname="Block1"type="CashReturnReqBlock1Type"xmlns:xs="http://www.w3.org/2001/XMLSchema"><xs:annotation><xs:documentation><pxmlns="http://Hps.Exchange.PosGateway">Contains a series of required and optional elements</p></xs:documentation></xs:annotation></xs:element>