I'm also dissapointed to see that its not included on this CD. I liked the accoustic version in the trailer better than the electric on the Funeral album. I can't tell wether the song is edited to fit the trailer's length or if its actually just 1 minute long.
Often times the trailer is just for that specific purpose and is not licensed for the soundtrack, songs / sound recording gets really complicated mainly so certain people can get theirs, hint: it isn't always the artists either. Maybe AF will release a version, seems like there is enough demand for it. just like that irritating themesong (remember when shows actually had themesongs?) for Friends, they only recorded that opening blurb. people kept calling radio stations for the song, the group eventually wrote out an entire song. so if a wonky song from Friends can be made to happen, then surely something of far more quality such as Arcade Fire can come into existence.