[Exim] radius auth problem

Hi,

I need some help because we want to do smtp auth against radius and I
don't get the right authentication-string to the server.
It seems that the string expansion in the authenticators is faulty but I
don't know how to setup the right variables that username and password a
expanded to the right radius-variables. I use exim-4.20 and
libradiusclient-0.3.2

Here is our authenticator's config:

radius_auth_plain:
driver = plaintext
public_name = PLAIN
server_prompts = :
server_condition = ${if radius{$1:$2}{yes}{no}}
server_set_id = $1

radius_auth_login:
driver = plaintext
public_name = LOGIN
server_prompts = Username:: : Password::
server_condition = ${if radius{$1:$2}{yes}{no}}
server_set_id = $1

And here the tcpdump that I get about exim talking to radius:
(mechanism auth plain)

17:14:26.851306 zoidberg.futurama.student.uni-augsburg.de.1108 >
dill.rz.uni-augsburg.de.datametrics: rad-access-req 63 [id 213] Attr[
User{\0user\0password} Pass Service_type{Authenticate Only} [|radius] (DF)
17:14:36.847697 zoidberg.futurama.student.uni-augsburg.de.1108 >
dill.rz.uni-augsburg.de.datametrics: rad-access-req 63 [id 213] Attr[
User{\0user\0password} Pass Service_type{Authenticate Only} [|radius] (DF)
17:14:46.847693 zoidberg.futurama.student.uni-augsburg.de.1108 >
dill.rz.uni-augsburg.de.datametrics: rad-access-req 63 [id 213] Attr[
User{\0user\0password} Pass Service_type{Authenticate Only} [|radius] (DF)

As you see the hole string is expanded into the User-field and there is no
reply from the radius-server because of the wrong username.
It seems for me that exim should pass the password to the Pass-Field...

Please give me some help.

Thank you,

Roman Dilken, University Augsburg, Germany