So my solution was: removed courier, maildrop etc. installed dovecot using this
http://www.howtoforge.com/perfect-se...64-ispconfig-3 manual, reinstalled ispconfig 3, in /etc/dovecot-sql.conf changed query from
user_query = SELECT email as user, maildir as home, CONCAT(maildir, '/Maildir') as mail, uid, gid, CONCAT('maildir:storage=', floor(quota/1024)) AS quota, CONCAT(maildir, '/.sieve') as sieve FROM mail_user WHERE email = '%u' AND disable%Ls = 'n'
to
user_query = SELECT email as user, homedir, maildir as mail, uid, gid, CONCAT('maildir:storage=', floor(quota/1024)) AS quota, CONCAT(maildir, '/.sieve') as sieve FROM mail_user WHERE email = '%u' AND disable%Ls = 'n'
and all works fine, autoresponder works to.