1) download this file [www.strategycore.co.uk]
2) put it into main folder of the game (with .exe files)
3) make your s3(or s2 - this fix works for both) run in admin rights and win xp sp3 compatibility mode or just disable steam overlay in-game
4) enjoy shadows and great lightning effects in your silent storm
....
5) if you still wan to upload a screenshots - make some, before you do this. and without steam overlay , just printscreen and copy&paste to the paint editor. After that - overwrite screenshots that you are already made before (without shadows) if you do everything right - upload screenshots through the steam that looks like screenshots that were overwrited by you , and here you go

shadows+ability to upload beatiful screenshots (more beatufiul than without shadows)