It's just my night rambling, but what would I do for example with walking would have been overriding GoTo method by your custom.
This method would at the beginning check if the action should be mirrored and if so, you make the mimic thing.
so in actor.script I'd write something like this:
method GoTo(posx, posy)
{
global isMirorred;
if (isMirorred)
{
var newX;
var newY;
// perform some recalculation of inverse coordinates in here and fill it in newX, newY.
actorMirror.GoToAsync(newX,newY);
actor.GoTo(posx,posy);
}
else
actor.GoTo(posx,posy);
}
It's incomplete, but could give you the idea.