[Beepcore-java-users] Question about creating multipart messages

Hi,
      I have a question or two about formatting BEEP messages.  I'm doing an 
undergraduate project at Temple University implementing IMPP through APEX and 
the APEX Internet Drafts describe a bunch of different ways to map BEEP 
payloads, including:

       C: MSG 1 1 . 42 1234
       C: Content-Type: multipart/related; boundary="boundary";
       C:               start="<1...@ex...>";
       C:               type="application/beep+xml"
       C:
       C: --boundary
       C: Content-Type: application/beep+xml
       C: Content-ID: <1...@ex...>
       C:
       C: <data content='cid:2...@ex...'>
       C:     <originator identity='fr...@ex...' />
       C:     <recipient identity='ba...@ex...' />
       C: </data>
       C: --boundary
       C: Content-Type: image/gif
       C: Content-Transfer-Encoding: binary
       C: Content-ID: <2...@ex...>
       C:
       C: ...
       C: --boundary--
       C: END

My question is how do I go about creating a proper message that mimics the 
example payload above?  I know I can use InputStreamDataStream to add custom 
headers to the message, but the fact that there are multiple Content-Type and 
Content-Transfer-Encoding headers and boundaries is confusing me quite a bit. 
 I understand the purpose of this type of BEEP message, I'm just a bit 
confused on how to go about creating the message itself.  Any suggestions or 
examples on how to go about this would be greatly appreciated.  Thanks for 
your time.

-Mike Riggio