Shuriken mesh size over lifetime question

I'm using the Shuriken particle system to emit a single piece of geometry (a hollowed out cylinder) which I want to scale along the Y-axis by a curve over its lifetime. I tried using Size by Lifetime but I can't see a way to confine the size to a single axis - its all or nothing. I've also tried adding the Animation component to my particle system and using a compatible .ANIM file with the scaling effect I need, but it doesn't appear to do anything to the particle. It only works if there is no particle system. Any hints?