Receiver SOAP Adapter Problem-soap fault: Server did not recognize the valu

I have a scenario for service orders using async call : IDOC-XI-SOAP.

I used the XML Spy tool to test the Service order's web services and it works fine. I imported the same WSDL file in XI. When I send a SOAP message from XI, I get a following error in the adapter engine.

<i>MP: exception caught with cause com.sap.aii.af.ra.ms.api.RecoverableException: SOAP: response message contains an error XIAdapter/PARSING/ADAPTER.SOAP_EXCEPTION - soap fault: Server did not recognize the value of HTTP Header SOAPAction: AddUpdateCostObjectLevel1.</i>

Can someone please help me...

Thanks in advance!

Mrudula