Transformation from com.bea.wli.sb.sources.XmlObjectSource to com.bea.wli.sb.sources.MessageContextSource is not supported

in OSB, when using a SOAP with Attachment in a Proxy with OWSM Policies, you get this error message:

Transformation from com.bea.wli.sb.sources.XmlObjectSource to com.bea.wli.sb.sources.MessageContextSource is not supported

This is described in Oracle DOC "Combined use of SOAP with Attachments and OWSM Policies now Supported in OSB 11.1.1.7 (Doc ID 1347447.1)".

The solution is: upgrade to OSB 11.1.1.7. Or give up attachments. Or give up OWSM. Ok don't tell me I am stupid because I already know.