Flat toggle button in Silverlight 4

Question

I know how to create a flat style button with just the image showing unless the user hovers over it or when it's pressed. I don't know how to do the same thing for a toggle button. I need it be flat (image only) in a normal state but when the user hovers over it or when it is pressed or when IsChecked=True the state behaves like the default toggle button. I tried modifying the Normal state only but when I do, the MouseOver state no longer behaves the same way.
Any ideas?
Let me know,
Aaron