Corrective blendshapes import problem

Hi all.

I created an animation in Maya with facial expression using blendshapes. The character is a dragon and he has a goatee.
I’m opening and closing his mouth with the blendshapes but the goatee movement is joint based. In Maya I made a corrective blendshape that moves the mouth joints so the goatee follows the mouth and so I can animate it normally.

And everything is working for now.

For importing blendshapes in UE I havee to go through 3dsMax (I don’t know why but if I export from Maya UE doesn’t recognize my blendshapes animation curves and and the blendshape animation doesn’t work properly). Since normal .fbx export doesn’t recognize my corrective blendshape before exporting it I’m doing a geometry bake (in Maya) with control points and driven channels flagged (so it bakes animation keys on the single vertex), then I do a geometry cache and only then I import everything in max.
I reimport the fbx in max and everyrthing works fine (although it puts the point cache modifier above the skin modifier).
I then export from max and import everything in UE… and that’s when everything goes nuts.

First of all the blendshapes animation curves are different from the ones I made (the tangents are all messed up) but I learned how to solve it (selecting the keys in Persona Editor and changing the interpolation in auto. They’re not exactly my curves but they’re fine enough for me). The problem is that it doesn’t recognize the corrective blendshapes and so my goatee doesn’t work properly (it compenetrates, streches and stuff like that). What am I doing wrong?
Is there a way to fix it?

Just to simplify that’s my workflow:

  • Animating the blendshapes and the joints in Maya

  • Baking the joints

  • Baking the geometry (with driven channel and control points)

  • Caching the geometry

  • Exporting Geometry and Joints in .fbx (everything flagged in the export: animation, blendshapes, geometry cache with set, ecc… I’m exportin in fbx 2013 and/or 2014)

  • Importing the fbx in max

  • Exporting the fbx again

  • Importing in UE

If you could help me I would be really grateful.