Intel HD 3000, HDMI and 2560x1080

I recently purchased an ultra wide monitor, with a native resolution of 2560x1080.

This is great but it's only working with Windows ! Apple is limiting HDMI resolution to be no more than 1920x1080, for no reason at all. I read everywhere than I need to buy whatever cable or adapter and to use display port, but I just can't. I also tried SwitchResX but same problem, resolutions over 1920x1080 are not available.

So I searched for a solution, and I found something interesting there : http://ift.tt/1wx2AAF It seems that increasing the framebuffer size will set bigger resolution available.

But I can't find any info about this with an Intel HD 3000. Is someone have any clue about where to begin ? I guess it's happenning in AppleIntelSNBGraphics but that file is quite big...

Another question I'm having is, is this still the case on Yosemite ? Because I'm on Mavericks and I could do the update if that might solve this issue.

Thank you.