Cant see problem with that.
it seems that your script works.
So you cant see any difference when you use r_lightmap? Have you checked your lights? Maybe they are pointing the surface in a way that shadows are not generated. Try to put q3map_lightmapsamplesize 1x1 before q3map_normalimage command and remove rgbGen identity from the script.
I dont know much about those things myself either
Light bounce might affect to that too as it illuminates the surface from many directions.
- sorry for editing this post so many times. Im bit drunk right now.