How to make Collada model double sided in papervision3d

i have an animated collada of envelope module that have an animation of opening itself

now for seeing both sides of the envelope i set the

      oneSide = false

i added for tests a ColorMaterial.

but what i want is to have 1 color in the outside faces and another color in the inside faces

and i can't figure it out how to this.

Solution

i found some class that a very great men develop!!! that solove this: here is a link to download it it the last post on the page: http://papervision3d.758870.n4.nabble.com/How-to-get-DoubleSidedCompositeMaterial-working-w-Latest-PV3D-td781516.html#a781518