Gracias Manoel (Lito) Fentanes !!!!! After a very long stream of emails, he was able to pull it out for me ! I started to fly in Argentina more than 10 years ago, and I was never never asked for this authorization, but it seems that now it's necessary. During the North - South trip, only Mendoza control gave me trouble. But thanks to the nice help from the Argentinian Friends, and comprehension from FAA/ANAC, this was pulled out without too much trouble.