No I never heard the story on the song... though I agree it is pretty corny in English...
There are several different versions of the story, but the one I tell goes like this:
One of the very first Catholic Cursillo weekends was held in Spain at a monastery at the top of a mountain. After the weekend, the candidates were all riding down the mountain on a bus, talking about their experiences, when the bus broke down and they had to wait for repairs. It was evening on a glorious summer day, and so they all sat in the grass at the side of the road with a small family farm and a breathtaking sunset spread out in front of them and made up that song together.
