Tween over multiple keyframes

I am new to kool moves (V9), have had some flash experience. I am doing a HTML5 project. I want to make four balls drop smoothly in a perfectly straight line at the same time but each at a different rate. I put the balls at the top of the screen in the first key fram and then at the bottom in the next keyframe. It animates them dropping, but they all drop at the same rate. When I change the tweens per keyframe, it changes all of them. I moved the ball I wanted to move slowly a few key frames ahead, but I can not find a way to make it animate bewteen key frames. For example the ball is at the top of the screen in key frame 1 and at the bottom in keyframe 4, I want the ball to tween smoothly from keyfram 1 over 2 and 3 and then through 4. What are my options?

The way I would do it is to use movie clips. Create a different movie clip for each ball. The key frames in the movie clips can have different time intervals.

Flash export has a motion path option which would be the preferred solution but unfortunately it is not available yet for Html5 export.