This one exactly was recommended me off list to try and it worked well
with both prosody-dev and prosody-users googlegroups.
The only thing needed in order to import messages into my IMAP mailbox
flawlessly was removing CR from headers line ending because my mailer
does not parse such headers correctly (I have No subject, No date, No
from instead of fields with standard subject, date, from fields from
message, they are displayed correctly in message pane).
So I wrote simple script to remove those CRs from all the files and at
the same time sorted them into directories per year and month.
Now I am reading these messages at a convenient pace for me and looking
for some bits of wisdom usually present in such an archive, so it is
easier then to get the whole image and understand details of the system.
Sure, there will be questions and I plan ask :)
Regards,
Milan