Blendshape
From UMAWiki
Blendshapes (also called Morphs) are supported in the UMA system. They can be authored and imported into Unity on a FBX. Then when creating a slot they will transfer over and be stored on the slot to be accessible when the slot is part of the final UMA.
Workflow
1) Create mesh with blendshape or morph data on it. Refer to the modeling packaged used for how to do this.
2) Import your FBX in to unity. Make sure the "Import Blendshapes" option is checked on the FBX.
3) Build a slot like normal.
4) Verify in the slot data that the blendshape exists.