also, if you are allowed to use swa(soap messages with attachments), you can put the xml as an attachment
it will be mime type text/xml, or application/xml
i believe
j2ee web services implementations are required to support at least one of them. they are similar, you can use either one. text/xml merely is for more human-readable xml. either one is okay.
in wsdl, it will be 'string'.
and in
java it will be javax.xml.transform.Source