Actions bug in Shape key editor


I’m trying to do some simple shape key animation. I have made some shape keys, and in the Action editor ->Shape key editor I can create keyframes, and make a simple anim by blending a shape keys. Porblem is, when want to create a new action. I click add new at the action selector thingy at the bottom, and that new action is supposed to have a copy of the keyframes from the previous action/animation. But if I modify this, and go back to the previous action, that is modified as well. However it did work with an armature, I could make different actions like walk, crouch, whatever, but it looks like it’s bugged when used with shape keys. Is there some trick to it, that I’m not aware of, or is this really a bug?
I’m using Blender 2.49b by the way.