first of all, i am a very competent bike mechanic, i have stripped, and built many bikes. this is no ordinary flat however...

i was riding my specialised 2007 hardrock disc sport, (it was a really nice ride..) and i got a puncture, i only noticed about an hour after i got back, after cleaning and servicing. the front tyre was completely flat as a pancake. my problem is this, i have no idea how to get the tyre off the rim, it seems glued on.

ive tried getting my levers in there, and ive tried pulling really hard, but it wont budge, its like its attached to the rim permanently. does anyone have an idea of how to remove this ?? i have many bike tools in my set, but i have a feeling this wil require a specialist tool, or the guy from thw shop where i bought it.

any help would be greatly appreciated, im stumped.
thanks, tim