As far as I know, Festool doesn't sell them anymore.
But I do know when I visit a dealer here in Holland I sometimes find they still have accessories for the Basis on their shelves, so at least here it would be possible to buy what you need if you put some effort in it. We also have a lively trade in second hand Festools here in Holland, and it would be fairly easy to find elements of the Basis system.
But I have no idea how that situation is for you, in Norway. Never been there, don't know the market there. You have a lot of Festool dealers around?