How to copy a rest pose between armatures? I have two different meshes (A1 and A2) that are each skinned to an armature (B1 and B2, identical in setup) that currently have different rest poses applied. I want to copy the rest pose from armature B1 to armature B2, so they are identical. How would I go about doing this? 

I've tried using the Pose -> Copy Pose/Paste Pose feature between the armatures, but that won't work, as it seems to be using the current rest-poses as reference starting points, and those differ from one armature to the next.

Any suggestions?

I am using Blender v2.70 (can't use 2.71 due to FBX exporter not supporting shape keys).
You could use a Pose Library to store and reassign as many poses as you want.

A Pose Library  can also be shared among the rigs. Technically it is an Action, thus it can also be edited in the Action Editor mode of the Dope Sheet.