blendshapes to shape keys

Okay, I guess this is an old question but I simply cannot find the answer to it. If I build my mouth shapes in zbrush or Maya or Max and bring them into Blender as a series of meshes, how do I merge them into shape keys of my base object? I know there used to be a way (a script?) but I can’t remember how. I think this kind of workflow should be in the trunk. A check box on each shape key slider to pick an external mesh (like every other app :))

Any help appreciated.

Found it!

My own post too. :yes: