You can easily find your serverconfig.xml file within your Game Servce Control Panel. Once you've logged in, click on your Game Service and click the Configuration Files button. By default, there will only be two files here. Click the 'Text Editor' button to the far right of the serverconfigmain.xml file to open up the file within your panel. Alternatively, you can also access this file via FTP and edit it using a text editor of your choice.