RickSarg and Fifi:
I tried both your settings in every possible way, GWX only, SH3 1.4b, with my mods on top of GWX, GWX flat sun fix, etc, you name it,I've tried...
The result is exactly the same, the flat sun is still there.
The only benefit I got out of this long period of tests is that the image in general is fantastic, the jagged image is almost 100% gone and I am pleased with it.
After trying every piece of advice you guys gave me without positive result, it's obvious that something else is causing the flat sun, and I guess it has something to do with a graphics card setting. Until I can precise the origin of this, I will leave my current settings untouched, becuase I am very happy with the results..
Anyway, thanks a lot for your advices and time guys! We didn't fix the main issue, but something else good came out of it.
CapZap