standard Biped rig right arm export problem

[Manticor]

Hi

Im having a problem with exporting to a game engine with the default XSI rig (rig from biped guide).
The bones on the right arm are negative scaled which is causing a problem when exporting to our game engine.What is the quickest and easiest way to fix this problem .Im not much of a rigger and I dont really want to reskin the mesh and re-export all the animations.
Does anyone know of a solution to this.Ive tried resetting the scale and re-orienting the shadow bones to match the orientation of the left hand side but when I skin the mesh is messes up on those bones.

Thanks

M