I know this is not quite the same, but Camdenita suggested heating the blade of a knife with a lighter and that allowed me to put holes in my shelf to help me tie it on. You could try something like that. You have to be really careful because the knife goes through so easily that it'd be easy to make a mistake (perhaps practice on the middle of the circle which will be binned anyway, so you get the feel of it). Good luck, can't wait to see the finished extension.