Some Spring WS users using MTOM/XOP attachments might be interested in this Axiom bug:
https://issues.apache.org/jira/browse/WSCOMMONS-542

Check this out if you have problems with MTOM/XOP attachments (they get inlined as base64 even if they shouldn't). In my case, the request xml is given as a Source and the file attachments are added to the Axiom "dom" in a WebServiceMessageCallback (used the sendSourceAndReceiveToResult(Source requestPayload, WebServiceMessageCallback requestCallback, final Result responseResult) method in WebServiceTemplate) of
This bug probably applies only to such use cases.