Ok, so I found this bit in defaultcharacter:
EVENT IteratePlayersWhileInvisible
VARS
CHARACTER:_Player
ON
OnIterateCharacter(_Player, "GLO_InvisibleTurnStart")
ACTIONS
IF "c1&c2&!c3&!c4&c5&!c6&!c7&c8&!c9&!c10&!c11&!c12&!c13&!c14&!c15&!c16"
IsInCombatWith(_Player, __Me) //c1
CharacterIsEnemy(_Player, __Me) //c2
CharacterIsDead(_Player,0) //!c3
IsInDialog(_Player) //!c4
IsEqual(%InvisibleDialog, 0) //c5
CharacterHasStatus(_Player, INVISIBLE) //!c6
CharacterHasStatus(_Player, SNEAKING) //!c6
CharacterIsPlayer(_Player) //c8
CharacterIsSummon(_Player) //!c9
CharacterIsPolymorphInteractionDisabled(_Player) //!c10
CharacterIsPartyFollower(_Player) //!c11
CharacterHasStatus(_Player, KNOCKED_DOWN) //!c12
CharacterHasStatus(_Player, FROZEN) //!c13
CharacterHasStatus(_Player, PETRIFIED) //!c14
CharacterHasStatus(_Player, STUNNED) //!c15
CharacterHasStatus(_Player, SLEEPING) //!c16
THEN
Set(%InvisibleDialog, 1)
DialogStart(_, "CMB_AD_Comment_InvisibleEnemyTurn", _Player)
ENDIF
As you can see, i changed sneaking to evoke the same action as turning invisible (do nothing, i guess). Am I right here? If so, how do I turn this new script into a mod?