smtp with tls

[Heiko Eulenberger]

Hallo to all,
I'm running kolab2.2.beta3 on openSuse10.3.
Nearly everything works fine, but I can't use my ISP as a relayhost. I allways 
receive the following message in the postfix.log:

 (SASL authentication failed; server verena.webhoster.ag[212.172.221.11] said: 
535 5.7.0 Error: authentication failed: authentication failure)

My ISP only allows smtp with tls. If I use Kmail everything works fine.
I'm assuming that I have to change something in the main.cf, but I don't no 
where exactly an how.
Here are my changes that I made to my main.cf:

relayhost = verena.webhoster.ag
smtp_sasl_auth_enable = yes
smtp_sasl_type = cyrus
smtp_sasl_security_options = noanonymous
sender_canonical_maps = hash:/kolab/etc/postfix/sender_canonical
smtp_sasl_password_maps = hash:/kolab/etc/postfix/sasl_password

If I use my older ISP (that I terminated) I can send with smtp an the above 
settings.

So, I'm assuming if is a problem with postfix and tls.
Did somebody get the same problem?
Can somebody help me with the settings, please.

Best regards,

Heiko