I would try use the Lightwave curve system, which is also in the curve editor. It has parameters like Tension, Continuity and Bias.
The tension parameter is where you can create ease in. If you set the tension to 1, you got a perfect ease in.
You might want to google for the Lightwave graph editor, which in fact is much better than the After Effects graph editor. Try find some tutorials. It just works a bit different, but it offers 100% control to what objects do. The After Effects system can cause very strange quirks when you add key frames in between and it just doesn't behave right on many occassions. Sometimes keyframes split in two halves or you get no handles etc. You won't have that with the Lightwave / Xpression system.
#XPression