Here I use direct control and try to throw knifes at a Jeep Machinegunner.
http://youtu.be/AgwDq40jcyo
And here's a another thing I saw when I made the video. When I have a guy crawling and tell him to stab a guy I have to click twice. First he pulls out the knife and stands beside the sniper. Then I have to click again so he actually stabs him.
http://youtu.be/DunkmqksXw4