xsi woes exporting and importing into unity

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xsi woes ;) I use xsi 7.01 Crosswalk 4.1

1.) I export from xsi and tag the model in Mixamo, then to try and export the animation with the skin, and I get this ...

Error: The skeleton in the scene doesn't match with the specified json..aborting

Available Scene Options:

Scene Options:
--rps arg retargeting params
--skeleton arg JSON encoded target skeleton
--skeleton-file arg read target skeleton from file
--cmodel-id arg character model id
--cparams arg character parameters
--ctextureparams arg character texture params vector: [r1,g1,b1;r

2.) If I export the fbx from xsi and the try to export the animation from Mixamo witout the skin, the amination is 'wrong' in Unity.

3.) If I export from XSI and import into Milkshape and then import into Mixamo, the animation works fine. Only problem there is that Mikshape does not export the mesh (as far as I can tell). This means that I can't check for distortions without importing back into xsi, whi is a pain.

Any of this make any sense? I have a funny feeling I have done something wonky in my model. Any help is appreciated. Do you have a simple fbx that noobs could import and export arounf, for testing purposes?

Love your product and would love to nail down this workflow.

Randy