[exim] Authentication using saslauthd <-> cyrus_sasl

Hello exim-users,

what I've got here is not a real question, but more a problem in
understanding the authentication mechanisms.

I configured my exim (4.50 on Debian Sarge) to use salsauthd for
authentication. The authenticator looks like this:

sasl_plain:
driver = plaintext
public_name = PLAIN
server_condition = ${if saslauthd{{$2}{$3}}{True}{False}}

My saslauthd is configured to use PAM for authentication.
This works fine.

I first tried it using:

sasl_cram_md5:
driver = cyrus_sasl
public_name = CRAM-MD5
server_realm = server.linau.de
server_set_id = $2

sasl_plain:
driver = cyrus_sasl
public_name = PLAIN
server_realm = server.linau.de
server_set_id = $2

This did not work. I always got an error "535 Incorrect authentication
data".

What I want to know is: What is the difference between my
authenticator using salsauthd and the cyrus_sasl authenticators?

I thought that using the cyrus_sasl driver automatically means using
saslauthd's services, but I obviously got something wrong...

Maybe someone can shed a light on this and/or give me a hint to do
some RTFM.

btw: Philip, maybe you could include some words on saslauthd in the
exim specs?

Regards & TIA,
Christian Schmidt

-- 
Ein Abschied schmerzt immer, auch wenn man sich schon lange darauf
freut.
        -- Arthur Schnitzler