I live here as well. Actually anyone who holds a foreign passport can get the refund. All that you have to do is fill out the necessary paperwork with the merchant in question. They call it a tax voucher. When you are leaving the country you cash in the voucher and get your money back. The only problem is that they only refund it in pesos (as you're leaving the country. Makes a lot of sense right.) If you have been here long enough I am sure that you would have had to buy some items where the tax could have been refunded. Even if you are a DNI holder they would have no way of knowing this unless the passport to your country of origin has expired.
