How do I set up an out-of-office note for my weißensee eMail?

Access the following link [only in german]:

Log in with your weißensee eMail address and your eMail password.

Click on the "Autoresponder" tab

Then click on "active", enter your text,
enter a start and end date below and click on "Apply changes" [Änderungen übernehmen].