Morph shapes not updating in linked file.

hi guys,
I have rigged a file added few morphs on the globle controller,after that i linked that rig file into my main animation file and started working…
By the time i realised that i will require one more blend shape to achieve a certain effect.So i opened main rig file and added one more morph on the rig.Now i face problem that newly added blendshape doesn’t update on the linked rig.If i break down the link then it shows the property but value change does no change.I might be missing some basics it seems… help !! :eek: