[Dovecot] virtual mailboxes with postfix

I have set up postfix with virtual mailboxes stored via 

mysql, and using postfixadmin, and dovecot as pop/imap server My postfix and mysql setup are pretty much standard for postfixadmin, as described here http://postfixwiki.org/index.php?title=Virtual_Users_and_Domains_with_Courie... (except for the parts about courier-imap.) Everything appears to be working fine except actually checking and authenticating mail via dovecot. I am fairly sure all I really need is the appropriate incantations in /etc/dovecot/dovecot.conf and dovecot-mysql.conf - does anyone have this set up and working? I should add that I want to allow both virtual mailboxes, and also local accounts, so I presumably need to support two different kinds of authentication. Regards David