PV3D: Invert vertically a cube's face

Hi guys,

I’m studying some Papervision3D examples, and I created a cube.
I made this cube spins vertically, and two of his faces are inverted vertically (when are faced to front).
I’m using MovieMaterial to fill all the faces.

I just wanna know how, (with Actionscript) can I invert those 2 faces.

Thanks!

(Sorry for my bad english :stuck_out_tongue: )