You need to make a mod... if you edit original files, they will revert every time you connect to steam.
Post #57 is not applicable as my method does not involve manipulating the dll.
If you wish, I can make the mod for you. You'll have to give me an email address to send it to as I can't attach it to messages. The mod is very easy to make... you could probably do it yourself if you've any lua modding experience.
Let me know.