Hi agin!
By pure luck (and a little try and error) i found out that its possible. What i did was to change a line in the tren2.pd file (found in Program Files\Battlefront\T-72 Demo\DATA\scripts\)
there is a line
nf = ot_setmod, dummy, mod_fire, modfire_nofire;
i changed it into
nf = ot_setmod, dummy, mod_fire, modfire_fireatwill;
and the tanks on the firing range started to attack me!
Cool