First I created bootable Mountain Lion disk by restoring BaseSystem.dmg and copying Packages from root folder to /System/Installation. This was the easiest way to create bootable install disk which worked perfectly for me.
Now here are the problems I faced while installation and solutions which worked for me.
Problem: Computer restarts at apple logo.
Solution: Install latest chameleon boot loader to the partition and try again.
Problem: Black screen and computer goes to sleep after some time.
Solution: Problem with your graphics card. Copy appropriate graphics kext to Extra folder, rebuild Extensions.mkext and try again.
Problem: "Cant install Mountain Lion on this computer" Error.
Solution: Build a proper SMBIOS.plist using latest models of Apple products and put it in Extra folder.
Finally I was succeeded in installing Mountain Lion.
- PS2 keyboard and mouse: Works (ApplePS2Controller.kext).
- Sound: Works (VoodooHDA.kext).
- Graphics Card: Works (NvInject.kext).