Hey there.
Hey icarus_uk I will have to disagree with, when you say
always shot into the air.(sorry :-X)
I have been able to get a unit to target an object and
use the command fire["?","?"."?"] eg.
And make him shoot at the target. And when you re-arrange
the command he shoots in the air.
But lately havn't had much luck.
Hope this may help