[exim] exim4 - 550 relay not permitted

Hi everybody,

I am new to exim4. I need to use a relay server to send mail. I did the
following to realize it (I use Debian 3.1 with exim4):

- I edited /etc/exim4/passwd.clients and set the IP of the relay server,
my username and my password
- I edited /etc/exim4/update-exim4.conf.conf and set
"dc_eximconfig_configtype='smarthost'" and
"dc_smarthost='<IP-Address>'"
- last, I called update-exim4.conf and restarted exim4
with /etc/init.d/exim4 restart

after that I get this message in /var/log/exim/mainlog when trying to
send a mail:

2005-12-08 21:43:42 1EkSc7-0001h1-24 ** bf@??? R=smarthost
T=remote_smtp_smarthost: SMTP error from remote mailer after RCPT
TO:<bf@???>: host <IP-Address> [<IP-Address>]: 550 relay not
permitted

The Relay-Server was especially installed by my Provider because of
problems. So my username and password are authorized to connect to it.

Did I miss a setting/configuration? User, IP and password seam to be
right. I couldn't find anything in the Wiki or in the archive.

Hope you can help me - I am not very familiar with exim4.

--
Greetings from Ulm, Germany,
Bernhard