Auto-cast non-auto-cast ability

[Rybak]

Heloes Hive Workshop
I searched for some time, but to no avail, for some way of triggering autocast of a normal spell for a unit. All I want is to make a caster unit with meele attack range be able to turn on auto-casting of an ability which has, let's say, 700 range. Normal auto-cast skill don't work properly when they have different range than the unit, so there comes one problem. Another is that I want the given spell to cause damage solely inteligence-dependant, ignoring the damage from unit's attacks.
So, actually, all I need is a trigger checking when the unit is within 700 range from an enemy and means to attack it. All my ideas failed. Any help?

 

[Vinz]

Set the locations of the damager and the target. Check if their distance is greater than or equal to 700. (Distance between points)

 

[Rybak]

Yes, but what checks whether a unit intends to attack or not? The 'unit is attacked' when melee unit attacks works, when the attacker is just next to the target. The 'unit is issued an order...' works only after you click 'attack' and click on the enemy.