The 2 downloads provide the skin_config.xml files already. So, if you're 15.2 users, you're good to go.
If you're 15.1.3 users (like me), you need to do what BlackMagic10 said, but in REVERSE.
Rename skin_config.xml as <skin_name>.xml.
Then open it whit Notepad, and delete the row <string...