(sorry can't edit)
Anyway. All the things that people recommend for insominia don't help, which I am sure you have tried every single method out there, as have I, with little to no success. This wiki link as a link to it, but also other types of sleep phase disorders that are wrongly thought of as insomnia: http://en.wikipedia.org/wiki/Circadian_rhythm_sleep_disorder
Maybe your body is just not meant to sleep at "night"? If your schedule allows, can you get a good length of sleep at another time of day? If so, it could be a delayed-sleep phase disorder, which usually gets misdiagnosed as insomnia pretty much all the time.
Hi,
How are you? Aside from medical treatment for insomnia, you may want to try non-medical treatment for insomnia such as sleep hygiene, relaxation therapy, stimulus control, and sleep restriction. Several simple steps can be taken to improve your sleep quality and quantity. These steps include: sleep as much as you need to feel rested but do not oversleep, exercise regularly at least 20 minutes daily, ideally 4-5 hours before your bedtime, keeping a regular sleep and awakening schedule and avoid drinking caffeinated beverages later than the afternoon. If it persists, you may need furtehr evaluation. Take care and do keep us posted.