You can run CentOS + BlueQuartz (StrongBolt - see www.osoffice.co.uk), or you can run Rackstar OS (www.rackstar.net). Both are based on more modern Linux cores (Red Hat Enterprise and Fedora, respectively), and include more 550-like interfaces, which will give some additional control. They also both have modern versions of Apache, PHP, Perl, MySql, etc, and thus are more amenable to addition of other open-source packages.
You can also buy DirectAdmin, Webmin, or any number of other packages and have them installed on your system.
However, in truth it sounds like you should sell your Raq3 to someone who is familiar with them and buy a stock 1U Linux system running DirectAdmin or something.
So where is the file i need to edit to park a domain?
There is no specific file to edit. Your actually going throught the whole process of setting up a "website" You add a Virtual site and the dns for it. You can then click on the green wrench and then site settings. There you will find Web Server Aliases. in that box you can add multiple hostnames that the virtual site will respond to. (granted they have there dns correct)