[Dovecot] Only method=PLAIN

Hello

I need to authenticate dovecot against openldap. OpenLdap's authentication method requires SHA. How must I set dovecot ?

#### /etc/dovecot/dovecot-ldap.conf

hosts = ldap-server dn = cn=administrator,o=admin,o=ldap-server dnpass = xxxxx

# # # parametros de prueba default_pass_scheme = SHA # # # fin parametros de prueba

auth_bind = yes

auth_bind_userdn = cn=%u,o=usuarios,o=ldap-server

ldap_version = 3

base = o=usuarios,o=ldap-server scope = subtree

user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid

user_filter = (&(objectClass=posixAccount)(uid=%u))

pass_attrs = uid=user,userPassword=password

pass_filter = (&(objectClass=posixAccount)(uid=%u))

#########

/etc/dovecot.conf protocol imap { }

protocol pop3 { }

protocol lda { postmaster_address = manuel@mfernandez.es }

auth default { #mechanisms = plain SHA

    passdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
    }

    userdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
    }

    user = root

}

dict { }

plugin { }

If I uncomment #mechanisms = plain SHA Dovecot doesn't start, the error: dovecot: auth(default): Unknown authentication mechanism 'SHA'

Thank you