Reversing animation when a layer hides?

Hi everyone, hopefully someone might be able to point me in the right direction on this.

I've got a prototype set up that brings up a layer when you click the 'menu' icon. When that layer appears, it is animated to make its own icons fly in from the right and make a "toolbar" appear. No problem. There is also a small X circle to hide this layer, sort of a collapse effect. Good there too.

What I am trying to accomplish is: when you click that X to hide this layer, I'd like to animate this toolbar to fly to the right...the reverse of how they appeared. At this point, the only thing I can pull off is, when you close the layer, the icons just disappear.

I've tried to add exit animation to those layer shapes, but it's not happening. Is it possible to do even do this?

Attached is a simple example. Just click the "course list" button, watch the layer appear, and then click the X to close.

Thanks,

Blair