How can I install Aegir on a server managed by Froxlor?

I tried to install the Aegir 3 Debian package as described here on a server modified with Froxlor. The installation worked fine without any complaints, but when you try to access the Aegir installation, the Drupal installation screen appears.

Since Froxlor changed their Apache configuration files, I set up a Froxlor domain to access the Aegir installation, pointing to the directory where Aegir is installed (/var/aegir/hostmaster-7.x-3.161). But I'm not familiar with the Apache configuration, but I guess the Aegir probably needs its own Apache configuration files to work as Aegir database variables are given by Apache configuration files when Froxlor manages Apache.

Can someone give me a hint how I can solve this problem?