Ah, yeah, I see what y'er trying to do. Ye would need to edit the weather.particle's file in order to change speed and direction. It has something to do with the X, Y, Z, and yaw. I'm not sure what would fix the angle. Since I've never edited particles like that, but I can look into it.
Ye could also try the Ogre program like Ruby suggested. 'Tis probably a lot easier than messing with the file itself. >v<
Also, I'd be happy to give ye that. Sorry f'er not doing so sooner, but in all honesty, I completely f'ergot. I'm usually able to access the computer around 4, so ye should 'ave the files sometime around then.