event_attack is triggered when someone do an attack or dmg to the monster, it was not sufficient because I needed the npc to react  in general when he is aggroed by the player, it can be by entering in its aggro range, casting a spell on him, or attack or doing dmg to him too
here are the updates :
in attack.cpp : function Mob::AddToHateList
just after : ~line 2070
add this :
	Code:
			parse->Event(EVENT_AGGRO, this->GetNPCTypeID(), 0, this, other->CastToMob());
 in embparser.cpp : function PerlembParser::Event
just after : ~line 273
after :
	Code:
			case EVENT_SIGNAL: {
			SendCommands(packagename.c_str(), "EVENT_SIGNAL", npcid, npcmob, mob);
			break;
		}
 add this :
	Code:
			case EVENT_AGGRO: {
			SendCommands(packagename.c_str(), "EVENT_AGGRO", npcid, npcmob, mob); 
			break;
		}
 in event_codes.h:
add at the end :
	Code:
	#define EVENT_AGGRO		11
 that's all =)