Hi,
I've tried your method, but my laptop won't boot from the USB stick.
My laptop specs like this : Lenovo Thinkpad Edge E420 1141-7UA, Intel® Core™ i5-2410M (2.3GHz turbo boost up to 2.9GHz, 3MB L2 Cache), Intel® HD 3000 Graphics, RAM 2GB DDR3, HDD 750GB, Intel® Wireless 802.11b/g/n
It's a sandy bridge, is your method works on sandy bridge?