there is a software package out there called p2kman, for that particular modification it is a simple file replacement. I recommend backing it up. I also re-worked the menus, enable some features, re-mapped some keys, etc....
planetmotox has the software you need.
READ EVERYTHING SEVERAL TIMES BEFORE YOU DO IT. I can't stress this enough, people have turned their phone into a nice and expensive paperweight (brick) Many of the things you can do to the phone can and will void the warranty.