BPM - Unable to generate message from BPM in PI

Hello Experts,
I am using a test scenario using BPM which has only two steps Receive and Send step. The scenario flow looks like  File-> BPM-> ECC. File posted from the external file system is picked up by PI processed successfully and sent to teh Integartion Process.
However the later part i.e BPM is supposed to receive this processed message (MATMAS) and send it to ECC. There is no PI message generated for BPM -> ECC part.
I have ticked the Start Process flag in Receive step. Am i missing something else?
Kindly advice.
Thanks and Regards,


Hello All,
On testing teh configuartion in ID my scenario works fine and all steps are tested successfully, wheras when i try manually triggering the message from RWB, message fails in Pi with the following error:
<!--  Call Adapter
- <SAP:Error xmlns:SAP="http://sap.com/xi/XI/Message/30" xmlns:SOAP="http://schemas.xmlsoap.org/soap/envelope/" SOAP:mustUnderstand="">
  <SAP:P2 />
  <SAP:P3 />
  <SAP:P4 />
  <SAP:AdditionalText />
  <SAP:Stack>Unable to convert the sender service BPMTriggerAcknowledgement to an ALE logical system</SAP:Stack>
I have already tried following this thread IDOC_ADAPTER - ATTRIBUTE_INV_SND_SERV
Is there anything else to be taken care of?