I am pretty sure that the pillar 3a is only for the allowed by the goverment money 6000 something. And on this money you get the tax back by completing a tax adjustment tarrif form. You get this one online, or if you dont speak german go to the steuerverwaltung of the town you live. In Basel they were very helpfull with me and they spoke english.

If you want to put any more money on pillar 3, they go on 3b which is a totaly seperate thing.

You cannot backdate the payment. So now you put money for 2011.