You can change the name or welcome message of your server either through the TeamSpeak 3 client (on your personal Windows/Linux/OSX/etc. machine), or from your TeamSpeak 3 control panel. In order to do so, follow these steps after logging into the control panel:
1- Click "Game & Voice Management".
2- Click "Voice Services".
3- Under "Actions", click "TeamSpeak Browser". Your server port and name will now appear.
4- Under "Settings", modify the "Name" and "Welcome Message" boxes as needed.
If you have any trouble, please be sure to open a support ticket to contact us so we can investigate.