Rotation based shape key drivers, need some help with them.

I can’t find any tutorials on shape key drivers driven by rotation in 2.5(plenty for using transforms for driving and/or for 2.49). I would appreciate any links or advice about using them. I’ve got corrective shape keys for my legs done, and for the life of me can’t figure out how to hook up the thigh bones’ rotations to the shape keys.

I thought maybe using the thigh bone that’s also being used for deformation may not be allowed, so I tried duplicating it, turning deform off of it, and only using it to copy the rotation of the thigh, and it didn’t work. So I thought maybe I just can’t use a bone in the armature to drive with rotation, though I can with translating(a bit irrational). So I tried parenting an empty to the shape key driving using the x axis rotation: no problem. Works exactly and as easy as I thought it should. but as soon as I get the empty to copy the rotation of the thigh bone, no go. Is this a bug or maybe I’m missing something simple, or something, my brain is mush…