Deratox

Hey there, i just was wondering where in source the visiblity of auras is handeld. I have some npc flagged as trigger. On those some spells are casted which apply an aura, but i can't see any visual effect until I activate GM. I found the function IsNeedSendToClient in SendSpellGo but for me there's no check included if creature is visible for player or not. Or do i have to set any special flag in DB to get those auras visible? Kind regards