Toon shader shows outlines in editor, but not in game views

Hi, I've applied a toon shader to some meshes - and it looks great. The cell shading works and the outlines are there in the editor, but when I run my game, and view it in the game window, the outlines are not there - the cell shading is active in both editor and game view - it's just the outlines that go missing.

I am building for IOS. I have made sure the scale of the objects on the screen is 1. I don't think they're particularly small models.

Any ideas what's going on? Or what I could do debug/resolve this?

I'm using Unity 3.5

Thanks,

g.