Just wondering whether MTOM support was on the road map for SI WS at all? My use case is that I essentially act as a proxy web service, so a consumer sends me a SOAP request, I then make that SOAP request to the 'real' web service and send the SOAP response back to the consumer. At the moment I'm achieving this using inbound and outbound gateways and I have one scenario where i'm receiving an MTOM attachment and the the outbound gateway (or spring ws components) seems to resolve the attachment and the resultant SI message has the base64 encoded data in the payload. What I ultimately would like to do is send the response back with the MTOM attachment however that may be possible. I'm assuming this is a job for SI as it looks as if the inbound gateway deals with creating the response.