backup folders in imap server: agent ?

[Uwe Brauer <oub@mat.ucm.es>]

Hello

I would like to backup some of my folders in my imap server.
I usually connect via the nnimap backend using the agent.

    - is  it possible  to   de-synchronise  the  agent  from  the
      server. That is I would  kill certain message on the server
      but they would stay in the agent? It seems that this happen
      if   I delete messages   with  another client like mozilla,
      however this seems insecure and not a real backup.

    - could I copy the folder say  to a local archive, in mozilla
      for example  it seems possible  even  to drop and drag  the
      imap folder to the local folders. However I don't want to
      read the local messages with mozilla, but with gnus. In
      this case what would be the best backend. So far I have
      downladed some message in the mbox format using 
(setq gnus-default-article-saver 'gnus-summary-save-in-vm)
      but from that folders I cannot copy back messages, so I
      should use a different backend.

Can anybody give me and advice, what is the best procedure to
make a real backup of my imap folders and which backend to use, 

Thanks 


Uwe Brauer