Well, finaly solved it.
As I thoght, one kext was missing. Now I'm not there and I don't remember which one it was, something about AppleSMBIOS.
Graphics were stuck at 1024x768 and without QE/CI, as expected, but worked.
Then, by using a DSDT.aml which was already prepared for this board, graphics work wonderfully with QE/CI at 1920x1200 on my 24" monitor, without using any special driver, injector or kext string.