mirroring polygon blend shapes
 

I am setting up my character for facial animation and I am having trouble solving what I think ought to be a simple problem. The head is modelled with polygons and I want to be able to create some mirrors of the blend shapes I am making. IE when I make a left blink shape I want to mirro it and use it for the right eye as well. Same for the eyebrows etc. What I am doing now seems to result in the face flipping when I use the shape. How do I make this work?

Cheers,

Pat