TFS 0.X help to configure this boss rank script [TFS 0.4]

[pisquila]

Sorry for the spelling, I'm using Google Translate.
Could someone help me with this boss rank script please, I would like it to show the boss rank, just like the normal rank. However, it is showing another rank and not the boss's, the amount he killed

local monsterRanks = {
['ASTRA'] = {0},
}

function onUse(cid, item, fromPosition, itemEx, toPosition)
local monsterName = "ASTRA"

if monsterRanks[monsterName] ~= nil then
local str = getHighscoreString(monsterRanks[monsterName][1])
doShowTextDialog(cid, 6500, str)
else
doPlayerSendTextMessage(cid, MESSAGE_INFO_DESCR, "Monstro não encontrado no ranking.")
end

return true
end