Argentinian Commandos

Thats a Blowpipe Anti Aircraft Missile, did the Argys have them ?
Great pictures

Have a look at this site
Falklands War

There's a photo of Argentine Blowpipe operator trying to fire his weapon at an attacking Harrier.

It's also a great site with information on the war.

Also found this on the web:

"Blowpipe was used by both sides during the Falklands War in 1982. With the targets being fast flying aircraft, flying low and using the ground to hide their approach the Blowpipe had about 20 seconds to spot the target, align the unit and fire. A British officer compared using the weapon to "trying to shoot pheasants with a drainpipe." The official report stated that of the 95 missiles fired by the British, only 9 managed to destroy their targets and all of these were slow flying planes and helicopters.

A later report determined that only two kills could be attributed to Blowpipe: A British Harrier GR3 (XZ972) and a Argentine Aermacchi MB-339A (0766 (4-A-114)). Blowpipe was found to be particularly ineffective when used to engage a crossing target or to chase a target moving rapidly away from the operator. The poor performance led to it being withdrawn from UK service."