The shape of the Body subtree depends on the WSDL style and a child of the Body subtree is generated in such a way that an rpc-enabled message model generated on WSDL import, correctly matches the shape of the tree at runtime.
Note that attachments for an MTOM message are represented inline as part of the SOAP content in a base 64 representation.
The SOAP parser does not throw an exception if it does not recognize the operation. However, you can configure the SOAPInput node to reject or accept unknown operations as required.
The SOAP part is identified by the Content-Type start parameter or, by default, is the first part of a SOAP with Attachments (SwA) document.