er...
nono...that's a cool feature, anyway, for producing lightmaps among other thing..
what he ask for is...He surely has a rig, with constraints of the kind: ik solvers, track to, copy to, etc...he wants to bake em, cause if not, the x export will be wrecked (md5 exporter instead does this well, no extra action needed. x may have in a future. )
In Blender 2.43 , the final release (what you download in blender.org, not a non final build) , do this :
* go to Action Editor. (the buddy running icon)
* there where u see a "pin" icon, you will find near a button, "Bake".Click it.(unsure if u need the armature in pose mode with all bones selected...surely not)
* You still in the standard action, the one you used to work. Besides the pin icon, you see a double arrow icon, click it to deploy the list of actions...choose AC:Action.Baked (is the name unless you renamed your initial action, could be AC:UglyOgre.baked , for example, then...) .This way you are using THAT action, the baked one, and you want to use it for exporting (surely NOT for continue editing! ) . You should see now in action editor how keyframes for EVERY bone have populated every frame. Now export. All bones have a keyframe per frame, it "baked" what ever the constraints where doing exactly, but output in standard bone keyframes that the exporter can deal with.