I see noone else have posted, but I'm not gonna give up just yet.
The song became popular after Disney used it in their 1942 movie "Saludos Amigos". Supposedly, there was a worry that some of the latin american governments could side with the nazis during world war 2, so aside from being just another Disney movie, this film was a part of an attempt from the US at establishing a friendly neighbour relationship with the latin american countries. Supposedly!
This is the part from that movie containing much use of Aquarela do Brasil. The version in the movie is quite good (sung by Aloysio Oliveira) and the film itself is very entertaining, so it's well worth the watch.
