Messages recieved must contain the header "Content-Type" when the header does not contain this a IllegalArgument exceptions is thrown, "TransportInputStream contains no Content-Type header".
Though this is correct is the pure sense, there is no real specification for sending messages by means of MOM.
When the sender of the message is Spring-WS this does not impose any problems (the header is set) but when others, in our case Oracle BPM, sends a message the header is not send and where not able to process the response.
Possible solution, assume a default value for the "Content-Type" header is message from the MOM. content-type=text/xml?