after creating context which supports multisampling i create FBO which resets GL_SAMPLE_BUFFERS value and i can’t use alpha to coverage option. if i render my scene without using FBO everything is fine. is there any solution for my problem?
p.s. i’m using an ATI x1800xl card
When using an FBO, you replace the framebuffer you render to, and with it the multisample config and formats. To get multisampling with an FBO, you need to create a multisample FBO. The extension EXT_framebuffer_multisample allows you to create one and EXT_framebuffer_blit allows the multisampled framebuffer to be resolved to regular FBO.
-Evan
you know, i checked my video cards (6800gt and x1800xl) and none of them supports the extensions you mentioned 
ATI has no support for it, Nvidia cards have support enabled in latest beta drivers 91.47 (G80 drivers)