Hi Holger,
>Is it possible, that I have to restart Outlook or have to wait some hours for activation ?
no. The Exchange transport service is restarted during installation but after it finishes its initialization and starts to process messages, the DisclaimIt agent should be active.
Could it be that you configured a distribution group filter on the Exchange transport rule? This could maybe explain it because the Exchange transport service caches group membership for four hours before refreshing.
-Franz