I seem to recall the female was imported whilst pregnant, and gave birth after arrival - thus this is not counted as a captive breeding of the species.
You were right Chlidonias ! The Zoo obtained these animals as being a Giant armadillo mother with 2 young but later these 2 young proofed to be 2 specimens of another species !
A member of the belgium version of ZooChat ( Laafse Kikkers ) helped me with the Giant armadillo problem and gave me the following information :
1965 A female Giant armadillo called Santa obtained with 2 smaller ones which later proofed to be Southern naked-tailed armadillos ( Cabassous unicinctus ) - well seen TLD !
End of 1965 - beginning 1966 a second Giant armadillo was obtained, a male called Tatou.