Pitcher:
Claws-mail created a directory /home/user/.claws-mail/ to save his preferences. All mailboxe has a directory in your home directory. If you have two mailboxes, for example foo1 and foo2, you have two directories /home/user/foo1 and /home/user/foo2 created. To save and restore data, the n800 provides a tool to save and restore data. But I don't if all the directories in /home are saved/restored? Especially the .claws-mail directory who is hidden.

EDIT: This http://www.maemo.org/platform/docs/h...#backup-custom explains that the backup application saves and restores user data stored in /home/user/MyDocs and claws-mail directories are created in /home/user/ directory. The backup utility seems to be not usable.

Other method, in a xterm, create a archive by :
tar cvz -f /media/mmc1/backup.tgz /home/user/.claws-mail /home/user/foo1 /home/user/foo2
to restore after the flash:
cd /home/user
tar xvz -f /media/mmc1/backup.tgz

markku:
I don't know if it possible to extract the mails from osso-email! Sorry.
But you can simply forward all your messages then get in claws-mail =)