matplotlib OO + navigationToolbar2GTK doesn't affect a figure in a notebook page

Hi list,

I successefully draw and add a matplotlib figure in a notebook page.
Thanks to John Hunter and it's powerfull FigureCanvasGTK.

I add a navigationToolbar2GTK.
But now, i am stuck to have callbacks when a button is pressed. Even the selection drawned when we use the zoom is not displayed.

How can i easily used callbacks ever written instead of rewriting all of them?
Thanks a lot,
Philippe Collet