Widescreen Issues

[Corvus]

Hey guys!
English is not my native language so I'll try my best to explain my problem.
I bought SA on Steam and dowloaded it recently. The game works just fine. But the widescreen option does nothing. When I activate it in the advanced menu, nothing happens. The resolution stays 4:3. Reboot Steam and my computer didn't change a thing, verify game cache neither.
I spent a few hours looking for a solution via google and every solution I found didn't work. Downgrade to 1.0 doesn't work (strangely), install fixes doesn't work, every attempt I made to solve my problem lead me to a dead end.
You're are my last hope guys! Please help me out! =D

[Blaagh]

There is no bug, these games (GTA III, San Andreas, Vice City) only have semi-widescreen support.

That "widescreen" -option only affects objects in the world like player, npcs and cars and adds some height to them, so they appear right. But everything else like world and hud and menu will always be 4:3 stretched to 16:9.