Hey desgraci, Away3D currently implements several types of culling, and most of them run by default with no need for you to do anything to enable them.
What you're talking about is actually a type of clipping. You can set the clipping property in a view to RectangleClipping, FrustumClipping, etc. I think that Rectangle is set by default. In both cases, the clipping works by ruling out of rendering any objects that fall outside of the camera's view. Face culling works automatically on any objects whose bothsides property hasn't been enabled. They will only be considered for rendering when the normals of their faces have a component towards the camera. Take a look at 3D engine theory, you will notice several culling and clipping techniques... The engine uses most of them.
