I found this in Galileo. It is a SITI fare.

AR1520B 22FEB AEPCOR SS1 740A 855A * TU
AR1495B 25FEB CORAEP SS1 435P 545P * FR

*PENALTY APPLIES*
LAST DATE TO PURCHASE TICKET: 15JAN05
$B-1 C01JAN05-SITI
BUE AR COR 198.00B2 AR BUE 198.00B2 ARS396.00END
FARE ARS 396.00 TAX 42.91DL TAX 12.67QN TAX 2.00TQ TAX 12.10XR
TOT ARS 465.68
BAGGAGE ALLOWANCE: 20K

EQU USD156.26
BANK SELLING RATE 1ARS EQUALS 0.3355705 USD
************************************************** ***

The SOTO fare is much higher. For the same flights, different inventories must be booked ==>
LAST DATE TO PURCHASE TICKET: 22FEB05
$BB-1 C01JAN05-SOTO
BUE AR COR 165.00YVD AR BUE 165.00DVD USD330.00END
FARE USD 330.00 TAX 35.76DL TAX 10.56QN TAX .68TQ TAX 4.06XR
TOT USD 381.06
E NONEND/VALID AR ONLY
BAGGAGE ALLOWANCE:
AEPCOR - 20K CORAEP - 30K
************************************************** ****
You need an AR agency. The major problem is that LAPA went broke and the others are hanging on. I've heard of something called LAFSA, but need updated information myself.