Sure, sorry for being inactive. Playing too much WoW, and since nobody post at the forums i dont check them daily anymore =(
Ok heres how it works, its quoted from other thread about grenade:
The grenade is a healing ward with about 2.5 sec duration. When the healing ward is created, i hide the grenade, create a archer that fires a grenade projectile and then i wait the time it takes for projectile to hit gorund (distance/1000) and then show the grenade again. When the grenade dies, i create the effects and kill all nearby units and barrels. The flashbang works just the same, but instead of exploding i create a flashfilter for nearby players.