detect when feral wolves is cast?

I am trying to make a custom spell summon 2 units so I am using the feral wolves (Orc Hero Spell) spell and transforming the units into other units. This works fine, except that the only way I can find to detect when they are created is using the "units enters map" option. However, this makes all spirit wolves into the new unit. I can't figure out a way to detect if the custom hero is casting the spell so only his summoned units will be changed. The "Is summoned" event does not work for the feral wolves even though it works for the treants just fine. Does anyone know which event the feral wolves trigger? Or does anyone have a better idea to detect who is casting this spell?
Thanks much!
-AZ

much easier solution:
1. open up the unit editor
2. modify all 3 feral wolves to BE the units that you want (dont make new custom ones)

thats it. when the spell is cast it will summon ur modified wolves (prolly not wolves anymore)

Thanks for the suggestion but I do not want to lose the ability to summon the feral wolves from the Orc guy. I just want to be able to summon the new units from the custom hero. Does any one know how I can detect when someone casts a summon spell or when the feral wolves are created?
Thanks
-AZ

This may or may not help, but I created an event that says, when a unit owned by triggering player is summon

action game time display to all player, name of summoned unit

Now, what this did, when someone summoned a unit it would simply display the name of the unit summoned, herein lies the problem. When I had my hero summon a water elemental, it said that I summoned a water elemental as it should, however, when I summoned feral wolves, it did not say jack, as though feral wolves are not considered summoned ??? Perhaps there is a different way of detecting if they are cast ??