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Use this transaction to enable so-called dummy booking for a given message type and company. Please note that dummy booking can also be enabled system-wide in transaction /PACG/ECM_CLSASSIGIN - FSM Connector's Incoming Messages Configuration (navigate to that link to see the list of objects supporting dummy booking).
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If this type of booking is enabled, no corresponding document/object is created on the SAP ECC/S4 side for a given FSM object. The FSM object will be confirmed/unblocked in FSM, but won’t affect the backend system.