ebXML Encapsulation

Some implementations may require that ebXML messages be Encapsulated into the payload of another ebXML message in a recursive fashion. This might be needed for encrypting a message where the headers need to be included in the encryption with the payloads. This might be useful when an intermediary node needs to add a payload to an existing message without disturbing a signature. This might also be used to break very large messages, or messages with large numbers of payloads, into smaller pieces for transmission (how this is done is outside the scope of this specification).

http://www.drummondgroup.com/pdfs/Encapsulation.pdf