Are you stymied by mydomain.com and www. mydomain.com ending up in different places, even though they should not? If your domain is on a server that uses Apache, and if you have access to the Apache directory (typically /etc/apache2), then it could be an easy fix.
In the Apache available sites directory (/etc/apache2/sites-available) should be an entry for each domain hosted on the server. It's common to copy and paste an existing one domain as a template for another.
Editing the file /etc/apache2/sites-enabled/mydomain.com shows the following: