I haven't seen the Shaymin movie either, but I know the Flower Paradise was used...it was just given a name that I can't recall at the moment. I DON'T know if the stone itself was used, but I don't think so. So it could possibly work, since if they didn't use it when they could have, they probably won't.
Now...how to lead up to this? *thinks*
And now I'm becoming tempted to help actually write this. ^_^