This is a risky suggestion that might end up ruining the binding itself. Try it at your own risk. You have been warned. I didn't use this for the Kalamar book but I have used it for other books.
I used a heat gun (the kind used for heat-shrink wrappings on model airplanes) to 'unglue' the binding. Not all of the binding, just the section that held the insert. A good hair dryer would work just as well. I then pulled the insert carefully out.
Now what I used to repair the binding was elmers glue. That really is NOT the best choice. I figure as the glue gets older it will become brittle and start causing me problems (it has been about two years now). I don't know what they use for true bookbinding but that would probably be the best choice.
later,
Ysgarran.