Hello, 
  
Thanks for the how to and the following posts, today I have successfully installed Mountain Lion (1.8.3) in a MBR disk using EDP. And the DSDT file provided by  EMlyDinEsH which solves the Black Screen at boot. 
  
But now I have a strange error that when I try to reboot or halt the computer, it hangs and appear again the Login Screen. Anyone does it know what could make this happen? 
  
Thanks  
  
Edit: The keyboard isn't working properly, the Command Key (Windows) isn't doing it's function :s 
Edit2: "alt" key appears to be the Command key, and the <> are on a different place (k55vm with Spanish layout)  
  
Edit3: All working except Webcam, when before was working