Address shown in Meeting Request

[CatiaL]

Hallo,

we use zimbra with the outlook connector. Our setting is such that each user_name
logs in zimbra as ID@domane.de.
The settings for each user are (zmprov ga user_name@domane.de)

mail: ID@domane.de
mail: user_name@domane.de

zimbraMailAlias: user_name@domane.d
zimbraMailCanonicalAddress: user_name@domane.de
zimbraMailDeliveryAddress: ID@domane.de

The mail are sent and received and replyed correctly, i.e. always user_name@domane.de is shown.
We have some problems with the meeting requests:

* user_name1@domane1.de sends a meeting request to user_name2@domane2.de
* user_name2@domane2.de receives a mail with the meeting request From: user_name1@domane1.de
* user_name2@domane2.de accepts the meeting request -> automatically the acceptance mail is not sent to user_name1@domane1.de but to ID1@domane1.de
* user_name1@domane1.de receives than eiter
- a mail From: ID2@domane2.de
or
- a mail From: user_name2@domane2.de
Accepted: ID2@domane2.de

do you have an idea why this happens and how to prevent it to happen?
Another question: do you have an idea on how to set the user_name@domane.de as main e-mail address instead of that the ID@domane.de (keeping the login with ID@domane.de) so that for example in the Outlook GAL the first entry is the user_name@domane.de, and then follow the ID@domane.de and the other aliases?

Thanks a lot