[Exim] smarthost, AUTH and different identities

Hi,

I'm using (Debian) Linux with exim v3. I try to have a setup as follows:

Several users (actually different identites of mine) shall be able to send
mail through my ISP, which uses SMTP auth PLAIN and/or LOGIN, using the same
account at my ISP.

My account at my ISP is ujr and I have a user ujr on my home PC. SMTP auth
works (config see below). However, if I'm logged in as another user, say
`test', mail is rejected. As far as I can tell from the log, this is related
to the fact, that exim appends AUTH to the mail commands.

How can I prevent that?

Now the relevant part of the config file:
...
remote_smtp:
driver = smtp
authenticate_hosts = postman.arcor.de
...
plain:
driver = plaintext
public_name = PLAIN
client_send = "^ujr^secret"
...

From the docs I found on google, this should work. But postman.arcor.de
complains about the sender's domain. However, this should not be the
reason, because the user ujr@??? can send mail. BTW, the reason
for the freeze is, that I first sent the mail before the dial-in was
complete. I only included it for completeness.

2002-07-22 16:42:52 17WeOi-0001Iw-00 <= test@??? U=test P=local S=318
2002-07-22 16:42:52 17WeOi-0001Iw-00 == ujr@??? R=smarthost defer (-37): host
lookup for postman.arcor.de did not complete (DNS timeout?)
2002-07-22 16:43:06 Start queue run: pid=5032 -qf
2002-07-22 16:43:06 17WeEV-0001ID-00 Message is frozen
2002-07-22 16:43:07 17WeOi-0001Iw-00 ** ujr@??? R=smarthost T=remote_smtp: SMTP
error from remote mailer after MAIL FROM:<test@???> SIZE=1351 AUTH=test@???: host
postman.arcor-online.net [151.189.0.87]: 553 5.1.8 <test@???>... Domain of sender address
test@??? does not exist
2002-07-22 16:43:08 17WeOy-0001JD-00 <= <> R=17WeOi-0001Iw-00 U=mail P=local S=1333
2002-07-22 16:43:08 17WeOi-0001Iw-00 Error message sent to test@???
2002-07-22 16:43:08 17WeOi-0001Iw-00 Completed
2002-07-22 16:43:08 17WeOy-0001JD-00 => test <test@???> D=localuser T=local_delivery
2002-07-22 16:43:08 17WeOy-0001JD-00 Completed
2002-07-22 16:43:08 End queue run: pid=5032 -qf

The setup I try should not be too strange. How can this be done if the above will never
work?

Thank you!
Ulf