..Myself for a quick fix il duplicate the object and its animation, put it into a group scale it (usually minus x) and il constrain the object to the new scaled version.. not perfect and results may vary but for me thats the quickest and easiest solution.
This is going to be really stupid suggestion but I'm just going to say it.
You could try mirroring the animation in blender and then exporting back to maya would be much easier.
I'm pretty sure the mirroring features in Blender is heavily reliant on the rigging setup in the same program. I don't remember seeing anyone porting a rig from another application and automatically get it to mirror.
Replies
..Myself for a quick fix il duplicate the object and its animation, put it into a group scale it (usually minus x) and il constrain the object to the new scaled version.. not perfect and results may vary but for me thats the quickest and easiest solution.
You could try mirroring the animation in blender and then exporting back to maya would be much easier.
http://area.autodesk.com/bonus_tools