probably not much help, but I've got those tyres and they come off easy....
don't resort to metal tyre levers - you may damage the rim and / or tyre.
Make sure you are starting it off directly opposite the valve (i.e. as far away from it as possible).
Make sure the first tyre lever is definitely right under the bead, but once it is, try and get the leverage distance between the point where it is under the bead and the flange of the rim as small as possible, giving you the best possible mechnical advantage.
Don't start off directly opposite the valve. Start off at 90-degrees from it.
Directly opposite, you want to get the bead as far into the middle of the wheel as you can, i.e. seated right in the bottom of the well, so that the bead where you're trying to lever is as slack as possible. And you can't do that with the valve in the way.