Exim AUTH with PAM - pls. HELP

[MINTA GHEORGHE ADRIAN <gygy@rdslink.ro>]

I try to setup an exim mail server with PAM auth. against system passwords. 
Unfortunately the authentification doesn't work:
/var/log/exim/mail.log:
localhost PAM_unix[2271]: authentication failure; (uid=8) -> gygy for exim service

Because the exim version in woody is very old is not suported anymore by the exim peoples, so I don't dare to ask this on exim mail lists. Could someone give me a hint what to do: install postfix (also old) or change something in my config files ?

Any hins ? 

-------------
/etc/exim.conf :

plain:
 driver = plaintext
 public_name = PLAIN
 server_condition = "${if pam{$2:$3}{1}{0}}"
server_set_id = $2
    
login:
 driver = plaintext
 public_name = LOGIN
 server_prompts = "Username:: : Password::"
 server_condition = "${if pam{$1:$2}{1}{0}}"
 server_set_id = $1
end
----------
/etc/pam.d/exim :
#%PAM-1.0

auth     required       pam_unix_auth.so
account  required       pam_unix_acct.so
password required       pam_unix_passwd.so
session  required       pam_unix_session.so