Ahh I remember trying to do one of these... it's a pain. You need to alter the fly height of a flying unit, and calculate a parabolic path from beginning of jump to the end of the jump. I hope you know your trig (that is, if you want it to look right) . Now, I have seen something that could be thought of as a jump...but I have no idea how to do it. If you have ever played DotA, there is a toss ability that throws any unit. I have no idea how its done though. Probably WEU.