after trying a test installation (since no feature list exists yet vor v3) it seems dovecot imapd/pop3d is not (yet) supported. is that planned? with ispconfig v2 it was pretty easy to get it running, but i'd prefer not to hack around much since it might cause problems on the next update ...
Dovecot is planned for 3.0.2 version which should be released very soon. See bugtracker.ispconfig.org for more information.