Edit wordpress-mobile-pack\plugins\wpmp_switcher

Ok, I’ve spent hours attempting to edit the switcher.php file in the wordpress mobile pack. Of course I can’t find the file anywhere! On all the forums I see people referring to a directory. What directory are they talking about? I’m relatively new to wordpress (I usually build my own sites). I’ve looked under themes, and plugins (the edit option) and can’t find anything. I just need to know how to access this “directory” and I’ll be ready to go.

Thanks in advance