The problem with a 5.1 QT is that I can almost guarantee that no one will ever be able to listen to it.
If you do create a 5.1 file, it will normally play the L and R channels out the default output of the computer, which will freak everyone out and make them think you forgot the dialog. Or it may not play audio at all, which is even worse. To correctly play the file, you must have a Mac with a 5.1 output chosen in system prefs. There are only a few ways to accomplish this and even then it relies on external devices being set up properly.