i use last dovecot rc23 with users/passwords in mysql

1. How can i define a sql query for each auth mechanism ?

2)Why i can't set "default_pass_scheme = login" in my dovecot-sql.conf? :

dovecot: Feb 21 09:46:22 Info: auth(default): client in: AUTH 1
PLAIN service=IMAP secured lip=127.0.0.1 rip=127.0.0.1
resp=AGFkaUBhZHJpYW4uZXUAcGFyb2xh dovecot: Feb 21 09:46:22 Info: auth-worker(default): sql(adi@adrian.eu,127.0.0.1): query: SELECT IF('adrian.eu'='',clear,crypt) AS password , user FROM mailbox WHERE user = 'adi' AND domain = 'adrian.eu' AND status = '1' LIMIT 1 dovecot: Feb 21 09:46:22 Info: auth-worker(default): auth(adi@adrian.eu,127.0.0.1): username changed adi@adrian.eu -> adi dovecot: Feb 21 09:46:22 Error: auth-worker(default): sql(adi,127.0.0.1): Unknown password scheme login dovecot: Feb 21 09:46:23 Info: auth(default): client out: FAIL 1
user=adi@adrian.eu dovecot: Feb 21 09:46:23 Info: imap-login: Disconnected: user=adi@adrian.eu, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured

3)Whi i can't use plain-md5 in dovecot.conf :

auth default { mechanisms = login plain <- plain-md5 passdb sql { args=/etc/dovecot-sql.conf } userdb sql { args=/etc/dovecot-sql.conf } }

dovecot: Feb 21 09:43:48 Error: auth(default): Unknown authentication mechanism 'plain-md5'