How to create a .com alias to a subdomain
If you need another domain name pointing to an existing subdomain, create a file in the subdomains conf directly like this:
vi /var/www/vhost/yoursite.com/subdomains/foo/conf/vhost.conf
contents:
ServerAlias "newaliasname.com"
ServerAlias "www.newaliasname.com"
then rebuild apache config like:
/opt/psa/admin/sbin/httpdmng --reconfigure-all