Is it possible for you to convert a FBX animation file to a BVH animation file? Or take the animation out of a FBX file and (again) convert it to a BVH?

I have a fair amount of experience using and modifying bvh files in Poser and have recently done some work with fbx animations but have not found a successful method of doing the that kind of conversion. While I don't want to absolutely rule out the possibility, I doubt it.Certainly it's not going to be an easy process. I suspect that external programmes would be necessary. First of all the figure's hierarchy have to match body parts need to use the same names and be in the same order. However, if anyone does know of a method I'd love to hear about it too.