You have to remember that the waist is the skinniest part of the ski. Unless you're mounting the ski well above center (which is extremely stupid), the brake will be located back from the center, where the ski is wider. This means that the part of the ski where the brake will be is wider than the 116mm waist of the ski. However, it shouldn't be a big deal. As long as the brake is a similar size, you should be able to bend it out to make it work.
I'd say you're good to go, you're just going to have to bend it a bit.