So finally my recipe:
I set up the dovecot in Debian 6.0 by executing the following three lines:
apt-get install dovecot-imapd dovecot-pop3d
echo "mail_location = maildir:/home/%u/Maildir" > /etc/dovecot/conf.d/30-mailLoc.conf
Well, I needed more lines to find out that what I needed were those.
I hardened security slightly by setting up a new ssh-key:
sudo rm /etc/ssh/ssh_host_* && sudo dpkg-reconfigure openssh-server
and changing pis password.
For a quick test I can recommend the small example at the end of:
dovecot -n prints the actual configuration.
Don't worry about activating encrypted connections. By default both SSL and non SSL versions are activated.
Hope this helps!