[Classpathx-javamail] Q: Building complex MIME messages

[Adam Bradley]

I've been writing a little application which will help me move from my
current remote mailbox format to a different format, mbox.

My 'example' source message is the following

                                  1
                                /   \
                               2     3 (file)
                            /     \
                           4       5
                          / \     / \
                         6   7   8   9
                       (file) \       \
                              11      10
                                \
                                 12

Does anyone have any grand ideas how I might go about doing this? 
Current I'm going through each message in turn and recording what the
MessageID(s) of its children and prepending the previous entry such that:

1    2,3
2    4,5,3
4    6,7,5,3
6    -,7,5,3
7    11,5,3
11    5,3
5    8,9,3
8    -,9,3
9    10,3
10    -,3
3    -

From this, I want to build a MIME message and maintain the hierarchy 
within the subsequent message.

Thanks for reading all this.  Any ideas?  Thanks in advance!
Adam