The WebServiceLookup step generates the SOAPAction header based on the operation name and the operation namespace. This is not correct. An additional setting for the soap action header is needed to store the soap action retrieved from the wsdl.
Relevant section of the 2001 WSDL 1.1 spec at http://www.w3.org/TR/wsdl:
"The soapAction attribute specifies the value of the SOAPAction header for this operation. This URI value should be used directly as the value for the SOAPAction header; no attempt should be made to make a relative URI value absolute when making the request."