Look into your ArmA2.cfg for the localVRAM entry ... should be around your true VRAM value (in byte). With the bug you also cant choose high quality settings + video memory inside the game.
Installed and back to 182.50 because the 256MB VRAM bug. :mad:
My specs: Intel Q9550, 8GB RAM, 1 x GTS 250 1GB runing on WIN 7 RC 7100 64 Bit and ARMA 1.01 DE