10.8.3
I have upgraded my asus rom BIOS to avoid using null power management.
http://www.tonymacx86.com/116-modified-roms-flashable-asus-z77-h77.html
If you don't have a modified rom check easybeast installation instead of User DSDT installation at the top of multibeast.
I have a same build and follow your instructions. If I connect one monitor to the DVI port, the result looks like the attached image (screen.jpg). However, if I connect 2 monitors to both DVI and VGA ports, HD4000 driver is loaded and it works fine on the DVI monitor, but have flickering screen on VGA monitor.