If you want to use the texture I posted, it has to be set to "1" (static)
it goes like this:
f1graphics.cfg<------------------->
graphics menu ingame0 (off)-------------------------------->off
1 (static)---------------------------->low
2 (composite)---------------------->medium
3 (projected)----------------------->high
Remember the first line of your f1graphics.cfg:
0 ; f1graphics.cfg controls all settings (default 0)
If you have that set to "1" the graphics menu ingame will have no effect because as it says, the cfg file controls all settings.
So, if you want to use my shadow texture, check that both the shadow type in f1graphics.cfg is "1" and ingame menu says "low" and it should work