[Dovecot] Dovecot/Django authentication

We've got an application in django that has passwords stored in both sha1 and pbkdf2_sha256 form. We need dovecot to be able to authenticate against the django database (we can't modify django to store passwords in dovecot's form, I'm afraid).

Has anyone done a dovecot authentication plugin to support these password forms (and/or any other forms that django supports)?

Thanks-

Tom