The "Dirty Dozen"....not *SOLVED*

I watched this movie years ago, I thought it was the Dirty Dozen, but to my disappointment it was not the movie when I rented it. I checked IMDB and read about the other Dirty Dozen movies that where made, and they do not seem to match the movie that I am looking for. The movie is about this commander who takes a group of criminals and trains them to take out a German stronghold on a mountain top during WW2. They train with a group of Canadian specialists. The 2 groups do not get along. As the training continues the 2 groups develop a respect for one another. There mission is to attack the stronghold by climbing a sheer vertical cliff and attack them from behind. I saw this when I was quite young and found it very emotional. What is this movie? Is it a D dozen movie that I did not find???