1. Download InstallMacOSX.dmg from the Apple link.
2. Download and run Pacifist.
3. In Pacifist click 'Open Package' and select InstallMacOSX.dmg.
4. Browse to Install OS X Mountain Lion.app
5. Right click 'Install OS X Mountain Lion.app' and select "Extract to Custom Location".
6. Choose the /Applications folder as the destination and extract it.
7. Run UniBeast.