Send IDOC to SAP no transaction log

Dear all
I’ve used SAP Business Connector 4.8 to send IDOC to SAP ERP 6.0. I’ve created a flow step as below to send IDOC to SAP


The flow is mainly handover XML data then construct IDOC and send it to SAP. Once we test run the flow. the IDOC reach SAP and successfully post on SAP. But there’s no transaction log in routing -> transaction log. Do you have any idea to solve this issue?