Feel free to post the link to http://www.kitesurfing-kiel.de
and especially to the safty-pages where ever you like to. Olli, the admin, is a friend of mine and he is surely happy if he gets some extra international traffic. I posted the page here because there were the answers to your question and not to promote the page.
The holes in the shackles are homemade. Use a drill on the thickest part of the shackle on the side that is not released. Olli wrote that you can put A ring through it, but not what ring he used. It looks to me like a better key-ring (or two or three of them). I can ask him if he is back from vacation.
If you donÃ‚Â´t want to drill a whole, use the configuration of the second last foto on the page with two shackles.