When I first heard the score and after that I watched the film, I realised that a lot of the music that can be heard on the album is not in the film. Well I finally realised it. I finally got a copy from Media Ventures Director's cut album, and then I heard a track by Klaus Badelt which is very similar to "Ambush" on the album.
Also another tracks, but this time you can hear it in the film, when Xavier try to locate Magneto but he goes into a coma or something like that.
This track on the Director's cut can also be heard.