Massimo:
Nice add-on but why just for fun. We don't have a ring particle field in Saturn's rings (yet). I think a few folks have experimented with adding one, but you are already well on your way. This would make a very nice permanent addition to Celestia. To make this really look like Saturn ring debris, ...
1. Triple the number and alter the size of the particles in the ssc file
2. Change the models to be rough spheres or other CMOD shapes rather than so angular. In fact, Celestia's basic models CMOD folder may already have enough obloids, rough spheres and asteroid shapes to suffice here.
3. Change their texture color to what scientists feel may be the most realistic color for Saturn rubble. Perhaps white/gray and rock colored mix ...

There is supposed to be a lot of rock and ice in Saturn's rings.
Just some suggestions... but I think you're on to something here!
Frank