On the American Mercenary crap, this is stated by a ranking Argentinian Officer in his own words which sums it up:
THERE WERE NO US MERCENARIES IN THE CONFLICT.
Is a myth. The english got confused because argentine officers and commandos spoke english with american accent.
English is taught in the Military College of the Nation (Officers Academy). The commandos in the Argentine Army were founding members of the School of the Americans, teaching to latinamerican armies to fight the communist guerrillas.
Major Aldo Rico is known for insult the british in english when they fought against him, and most probably the origin of the myth.