Can any body tell me the name of the vietnamese war film where a group of soldiers kill a vietnamese soldier and one of them cuts his head off and keeps it in his backpack as a goodluck charm until it starts to smell and is told by the others to get rid of it.

Yes I do remember this movie... it was called "Dead Presidents"(Dead Presidents (1995) (http://www.imdb.com/title/tt0112819/))... remember seeing this movie a few times a few years ago =)