Blender FBX import problem

I am using Blender for asset conditioning / editing to support my video game project.

One of the things I am using it for is to transfer armatures and animations between models from different sources.

I have a model of a horse that I am using for a jousting game, and I transferred an armature and animation to it from a different horse model. I successfully transferred vertex weights between the models, and have seen the animation work properly without unusual deformation in the Blender 3D view.

However, after I export the model into FBX format, then import it into Unity 3D, I get very strange deformations, like you can see in this photo:

Has anyone else run into a problem like this? I've investigated the following things:

• I've made sure to accept all scales on both the armature and mesh

• I've made sure that the mesh was scaled up to the armature rather than vice versa, to ensure that there are no problems with the animation curves, since they dont scale to the armature after accepting transforms

• I've tried normalizing all the weights

I've had success exporting animation from Blender before, however in those situations I didnt try to transfer a rig between models - I only edited and inserted a few frames of animation.

Im pretty confident that this is a problem either with the Blender exporter or with the way Im using it, as I have an alternate FBX viewer and I get the same result there when I import the model as-exported from Blender.

Has anyone had a problem like this before? Any insights into what I'm doing wrong, or how I can work around it?

Thanks,

BW42