We got it! A couple of days ago we received a letter from the Chamber of Commerce with our registration (required by law for all businesses – which includes non-profits). And today the letter arrived with our fiscal registration number and exemption from sales and income tax.
In true tradition of the tax department, de letter was almost unreadable, and was geared to several possibilities, most of which were not relevant to our situation. A telephone call to that same tax office did give us the good news – we are exempted.