Also posted on superuser.com ( http://superuser.com/questions/646550/webmin-new-virtualhost-apache-configuration-is-incorrect-how-to-fix ) for those of you that want the points:
Whenever I create a new site on one one of my servers which runs Apache 2.4, after visiting the URL, I'm being redirected ot the default website on that server.
When I look in the config file, I see the following in the header: <VirtualHost *:80="">
As soon as I change the * to the external IP of the server and restart apache2, it works!
This question remains: How can I fix this permanently? I already changed my /etc/apache2/sites-available/default config file to have the external IP of this machine instead of *:80 in the VirtualHost header, but that doesn't do sh!t.