Gaucho100K, SoFlyOn, I have not tried to withdraw cash with my Mastercard Credit Card. I presume I would run into the same 320,- pesos limit problem. Paying for several 1K pesos with it was no problem some weeks back either in Córdoba and BA.
FirstData also owns ownership of Mastercard and related brands here in Germany lately. That Maestro is no longer part of MasterCard was, as I had written, being told to me by a customer service guy from MasterCard; I do not remember if in the US or Germany, when I started to call around because of my withdrwal problem some weeks ago while being in Argentina.
As well as MasterCard being ArgenCard some years ago in Argentina, as well in Germany it has been Eurocard for ages, but as far as I know, with no local limitations.