[Dovecot] postfix + SMTP AUTH using DOVECOT AUTH DAEMON

hi ppl I'm the new member of the list. Looking at recent messages look like there is a way to do SMTP AUTH in postfix using the Dovecot AUTH daemon. Currently my Dovecot installation auth again PAM (local users) and a simple shadow file (for virtual users, I plan to move to MYSQL later). I don't want to have different databases one for dovecot a one for SASL.

Where I can found the POSTFIX patch, or better, some kind of helper daemon for Postfix.

thx A