VideoBios Vesa table

[Kova78]

Hello guys,

I'm studying the Video Bios and the Vesa standards
My aim is trying to figure out how this guy has reversed and forced the X550 Ati video card to work (in native mode) with other video resolutions and specially with other Hsync freq. (in order to use with the old Arcade monitors):
http://tinyurl.com/mgcqnar (scroll down to see all the supported video resolutions).

After reading ton of documentations found on google, I started to reverse, with IDA, the X550 Ati video card bios (that I attached), but at this moment it is very hard to me to find the VESA table presents inside (I have experiences on reversing, but never on the bios).

Somebody, smarter than me , would explain how to find the table inside the Vbios? How to interpret it?
In fact, I noticed that the vesa table format changes despite the producer: ati, nvidia etc.
After that I want to modify the crtc register in order to change the hsync frequencies

P.S.
This guy did something that I'd like to do: http://tinyurl.com/m4w42rt (I translated in English with google ).

Please help me
Thank you in advance for any response