several airtime on one server

Hello all,
I don't find here , I wonder how to have several airtimes on one ubuntu server.

Tell me if I am wrong :
- in apache config add ports in /etc/apache/ports
- add one user per airtime ( it is for 2 different webradio ) airtime1 and airtime2
- add both /etc/apache2/available-site airtime1 and artime2 setting ports in virtualHost item
- in each users home :
* unzip airtime instal
* set correct ports in application/configuration/conf.php
* run install

The only thing I don't understand is how set different entry point in icecast configuration ?