This is what it is called in English version of the CIDH's submission to the Organization of American States on the case of Raúl José Díaz Peña, of Venezuela, where in the Spanish version it is called "escrito de fondo":

Nota 11: "Las peticionarias señalan que para esa época un grupo de militares, quienes manifestando estar en observancia del artículo 350 de la Constitución de la República Bolivariana de Venezuela, se concentraron en la Plaza de Altamira en Caracas. Escrito de fondo de las peticionarias recibido en la CIDH el 7 de julio de 2009."

Notas 156 y 160: "Escrito de fondo de las peticionarias recibido en la CIDH el 7 de julio de 2009."
http://www.cidh.org/demandas/12.703esp.pdf

Note 11: "The petitioners point out that at that time a group of members of the military gathered at the Plaza de Altamira in Caracas alleging compliance with Article 350 of the Constitution of the Bolivarian Republic of Venezuela. Petitioners’ Brief on the merits received by the IACHR on July 7, 2009."

Notas 156 y 160: "Merits brief received on July 7, 2009."

Throughout this document, "fondo" is used as the equivalent of "merits".

"Petitioners’ Merits Brief"
http://www.supreme.courts.state.tx.us/ebriefs/10/10067105.pd...

--------------------------------------------------
Note added at 24 mins (2011-12-17 12:39:46 GMT)
--------------------------------------------------

The reference for the English version of the document quoted is http://www.cidh.org/demandas/12703ENG.pdf .