MessageTransmissionOptimizationMechanism (MTOM) is a W3C Jan05 recommendation for optimizing the transmission of SoapProtocol documents.
It is expected to make obsolete current day (mid 05) mechanisms such as DimeForSoap
A demo between DotNet server and Java client is shown at http://blogs.msdn.com/smguest/archive/2005/06/30/434218.aspx