separate back/front points rendering

i have a little problem while rendering a point cloud:
Each point has a normal and is enlighted.

But i like to enlight only the points whose normal is facing the light. And i’d like to render the other points in black.

is that possible with the fixed pipeline ?

I guess that’s it is easily possible when rendering faces (by specifying different materials for back faces and front faces).
But what’s does that gives with points ?