Hey, sry it took me so long to reply but I had a lot of stuff to do so my experiments got to a stop. I tried iATKOS, i could install it, but i had the same issue, couldn't boot. However it seems to be possible to achieve booting from that notebook, coz I tried kalyway, and I could install and boot it. I now have a kalyway installation and checked the HD300 drivers, but they don't seem to work. I'm pretty new to all this hackintosh, i don't really know how i can experiment with different drivers on kalyway,... I have read some posts that maybe lion should have better chances of success. Guess my next experiment will be installing SL (vanilla) and updating to lion.
EDIT: This seems like hot news. I was just searching to get iBoot again and saw they made a very promising update just 2 days ago! Check it out here http://tonymacx86.blogspot.com/
. "...adding support for the Intel HD 3000 GPU in Sandy Bridge CPUs..." which is the exact issue I had under kalyway. Another post confirms full kernel compatibility with the i7-620M CPU. I recon i won't be able to try this before the weekend or the next week. But I'll post here once I can confirm this for myself.