adding blendshapes to a rig breaks existing fbx-animations unneccesarily

Hi there,

I am working with characters that have both blendshape and bone driven animations. the rig (.mb) and the animations (.fbx) come in seperately into Unity.

Everything working fine until here. Now it was necessary to add a couple of blendshapes to the rig [visemes - will get controlled by code not by animation]. This 'new' rig however breaks existing blendshape animation with the 'old' FBX files. Unnecessarily I think.

Afaik blendshapes are index based in FBX and these indices didnt change [just a couple were added]. So is there a reason why existing blendshape animation in the 'old' FBX files is not working anymore with the new rig?

[P.S.: re-exporting all FBXes with the new rig from maya will solve the problem but is a very timeconsuming process - we are talking hundreds of animations...]

any hint greatly appreciated!