The scripting for animation is currently fairly limited. You can choose the animation column and some options through the Animation message:
obj << Animation( <Animate Column( column )>, <Animate Rate( number )>, <Forward|Backward|Bounce> )
But the actual stepping through values is not controllable through scripting, other than using JSL to press the UI buttons. I believe there are some related Wish List items - you may want to review those and add your vote or comments on what would be useful.
-Dan