domain not updating automatically

I have installed the plugin and had my developer do the work necessary to move the sunrise file to the /wp-content/sunrise.php and set it to ON in the wp-config file (see below what is in the config file).

But, the domain did not update. He had to manually go in and set the new domain name as an alias for the sub domain of the site that was there as part of the multisite installation. I thought with the plugin, it would just work....but his thought was it can't be nandled easily since it requires changes made to the system configuration file which the web server process doesn't have the rights to modify. The plugin info implies the web server has a virtual host with a wildcard that handles requests from any domain that points to the server, and that is not the case...

So, just wondering if there is something else we should be doing or some what to set up the server to allow for this... When I created an A Record at Network Solutions yesterday, it pointed to our server pretty quickly but when I pointed to the real domain in the plugin, the only way it changed was with him doing the stuff on the back end.

It seems like it can be done because that is why you are marketing that you can just tie it to pro supporters....and then it is just automated. So, wondering what we need to do to make it automated without manual work each time we need to do this.

define('WP_DEBUG', false);
define('WP_ALLOW_MULTISITE', true);
define( 'MULTISITE', true );
define( 'SUBDOMAIN_INSTALL', true );
$base = '/';
define( 'DOMAIN_CURRENT_SITE', '' );
define( 'PATH_CURRENT_SITE', '/' );
define( 'SITE_ID_CURRENT_SITE', 1 );
define( 'BLOG_ID_CURRENT_SITE', 1 );

define( 'BP_DISABLE_ADMIN_BAR', true );
define( 'SUNRISE', 'on');
/* That's all, stop editing! Happy blogging. */