I did the following:
At my host I setup a subdomain called subdom.maindomain
Herewith a new folder/directorie appeared in my site's fileslist called subdomain
(sub directory of 'public_html')
In this directory there is a 'index.html'
The original content was:
<html>
<head>
<title>
subdomain.maindomain.nl
</title>
<style>{ font-family: verdana; font-size: 10pt; COLOR: gray; }
b { font-weight: bold; }
table { border: 1px solid gray;}
td { text-align: center; padding: 25;}
</style>
</head>
<body>
<center>
<table>
<tr>
<td>Dit is een placeholder voor het subdomein. <b>subdomain.maindomain.nl</b>
</td>
</tr>
</table>
</center>
</body>
</html>
I changed this into a redirect
<html>
<head>
<title>Subdomain at maindomain.nl</title>
</head>
<frameset cols='*'>
<frame name='main' src='
www.maindomain.nl/subdomain.html' scrolling='auto' noresize>
<noframes>
<body>
Your browser does not support frames
</body>
</noframes>
</frameset>
</html>
Next to this I found, downloade and installed 'com_virtualdomains-beta-0-3-0.zip'
It's use is quite simple.
After installation you have to state the main domain name
And next you can add as many subdomains as you like, including the 'www'
So now one can reach the subdomain with
www.subdomain.maindomain.nl
If you want to see it IRL
www.bedlamites.nl = the maindomain
www.herle.bedlamites.nl is the subdomain
(login with Name: herle, PW: herle)