Just because it is custom made doesn't mean it can work on death. :P
Have you looked for any items that can work while you're dead? If there are any, you could copy their flags or whatever. Although, I don't see any flags like that.
I'm honestly not sure and I can't test this myself right now.
Yeah im abit confused right now also, i might just edit the killedplayer stuff to give them an aura and hopefully it will work like soulstone giving them the choice to corpse run or choose soulstone resurrection, as i cant see a possible way to get it to work, wowhead doesn't show an option to sort it by usable items in combat only in area/battleground so.