[Exim] SMTP Auth Pb

Hi,

I recompiled Exim to support Plaintext authentification.
In the configure file, i put:

** TRANSPORTS **
remote_smtp:
driver = smtp
authenticate_hosts = 0.0.0.0/0

[...]

** AUTHENTIFICATION **
fixed_plain:
driver = plaintext
public_name = PLAIN
client_send = ^user^pass

end

Exim starts without any error (sendmail -bd -15qm) and I checked the logs files and didn't find anything.
With my Outlook express I still can send email without having to authentificate.
Is it the authenticate_hosts the problem? Note that I want to allow anyone send emails through my Exim SMTP as long as they authentificated.

cheers
Guillaume