The OFP game engine is like a hurricane. Whenever possible, work with it, not against it. It is so good that sometimes it fools you into thinking it is a real life simulator, but of course it is actually much more limited. Go with the flow a little: if you want to do something, and it doesn't quite work, don't force it. Sit back, look out of the window for a little and rethink your ideas slightly. After all, your original idea - no matter how good - was arbitrary: it doesn't have any intrinsic value over any other idea.
Make a mission that brings out the best in the game engine: its less fun for you and less fun for the player if you are constantly fighting it. Apart from anything else, who is going to win in the end?
The answer is yes, in the end of the day, using setVelocity, setPos and playMove commands you might be able to get what you wrongly think you want. (There is no easy way - the collision avoidance routines are the problem.) But I strongly recommend that you apply a little flexibility to the situation. It's one of the secrets of good mission design.