I know exactly what you mean Silenoz. I can't get the speed and accuracy up to what it needs to be either. The song that REALLY annoys me is Pure Evil. Those triplets come at you fast, and they need to be played perfectly in time to sound right. Like Benoit said, just practice on keeping your hand motion as small as possible. Think of it as a "vibrating" motion with your hand....Fast and short. As for timing, that comes with practice. I still can't get it right, and be prepared for it to take a LONG time to learn.

Edit: oh ya, and don't use anything but heavy picks. And don't just practice starting with a downstroke. Because of the fact that they are "triplets", sometimes your going to find yourself needing to start with an upstroke.

Edit again:......and remember not to tense up your arm/hand/wrist too much because thats never good.