When header fields are present in the http body of a m-send-req (or other pdu), what is the purpose of the equivalent extension headers in the http headers (i.e. X-NOKIA-MMSC-MESSAGE-ID, X-NOKIA-MMSC-TO, X-NOKIA-MMSC-FROM, X-NOKIA-MMSC-VERSION, X-NOKIA-MMSC-MESSAGE-TYPE) ?
If the same headers are present in the http headers and the http binary body, which takes precedence? Do the http header values overrride the body values? What happens when values for equivalent headers conflict?