The correct steps are:-
1) Load the kext file:-
2) Dump the video ROM:-
Thank you kizwan.
With your new instructions, I was able to generate a video ROM file. One more surprise. Sleep works wonderfully now. I didn't do anything special. All I have is SleepEnabler.kext in the Cham boot partition and running with kokamal's dsdt.aml (modified GFX string for the Graphics model and also the totalsize + the IDT audio device string). Maybe, he has something special in his dsdt.aml for enabling Sleep. All I did is press Fn+F5 (there is a moon like icon for sleep) and the system went to sleep completely. After couple of minutes, I was able to wake up the system by opening the LID or pressing the Power button. So, sleep works extremely well which is a breakthrough. I'm surprised that the Fn+F5 key is working for Sleep. So, in the same lines, we can map all other Fn+ keys (including Brightness).
Also, I'm including kokomal's dsdt.aml and the original untouched dsdt.aml from Mammoth Boot CD 1.10. I'm requesting you to please patch the dsdt.aml (attached in this reply) with Audio, GFX string, Nvidia GT230M specific entries and/or Sleep (if any) and post it here.
Btw, do you think we can enable Intel SpeedStep just by adding iMac11,1 to smbios.plist as I read elsewhere? Also, I'm using the latest VoodooBattery 1.3.3 and it looks like I'm not getting enough juice out of it (maybe close to 90 mins for just doing light stuff). Is there a way to get more out of the battery?
Thanks for all your help and patience and thanks to Mammoth for the wonderful Boot CD 1.10 which was really a stepping stone to begin with.