Technically speaking, you only need to rip the game to get an ISO file, opening it with a program such as WiiScrubber, or unpack it with Wimms Iso Tools or something and replace the files of the disc with the modified ones of the translation (and repack it if you used the second method). I've done this with a couple of mods for Smash Brawl and Monster Hunter, and that's all I've ever needed to do.
In fact, the translator, Brand Newman (hello there!) did a PDF instruction booklet mimicking the ones from Wii games with exact instructions as to how to create a translated ISO. It's a pretty cute detail, so kudos to him.