Are both the Mediator value assignments (b2b.toTradingPartnerId, etc.) and the 'Internal-Properties' in the EDIFECS XML necessary to find the agreement in B2B?No. Internal-Properties is optional element in EDIFECS XML. You use it only when you want to override the document protocol parameters defined at B2B otherwise do not include Internal-Properties EDIFECS XML. Only B2B headers (b2b.toTradingPartnerId, b2b.fromTradingPartnerId, b2b.documentProtocolVersion, b2b.documentTypeName) are used to identify the agreement for outbound case.