Confixx can handle IDN (international domain names) domains including Umlaute (ä,ü,ö). Normally you should be able to type your domain into the Confixx webinterface including (ä,ü,ö) and Confixx should generate punycode for the apache vhost config and the dns zone files. This stopped working in Debian Lenny due to the apache package in Lenny which was compiled with LANG=C. To get this function to work again open the following file with your favorite editor:

vi /var/www/confixx/html/include/idn_functions.php

If you are using Suse you will need to look under /srv/www. And add the following line at the top of the file under the comments:

setlocale(LC_ALL, "de_DE.UTF-8");

Thats it IDN domains should work again.