Klein did make an adapter, it costs and when they come up, still sell for a lot of £. Its essentially a small metal tube with a ferrule on the end, and needs a zip tie round the tube. Not elegant at all. I did have one, and toyed with using it when I had a Klein, but didn't. I did contemplate the idea of modifying a v brake noodle so that it fitted in the existing hole, then joining it with brake outer to a noodle at the brake. Using Nokon outer would look much nicer, you could probably use a flexible noodle too.