You seem to have got it all figured out already
FTP into your server. Transfer the file to edit to your machine in ASCII (thsi is a setting in your FTP prog. if you having trouble with this, i can help).
Once you've got the file, MAKE A BACKUP on your local machine. That way, you are fine if anything goes wrong.
Open the file in a non-destructive text editor. Use BBEdit or Alpha if you have them. SimpleText will likely fry the file. Get BBEdit unless you have a good TEXT ONLY editor.
Apply the modifications as described in the mod's text file.
Upload the file back to the server (in ASCII!)
Check the mod works. If it doesn't, restore from your backup and start again.
The hack you are after is called "Who's Online" and is talked about
here .
Just a thought
