Lua [TFS 1.0] Specify damage values for custom monster spells?

[Tufte]

    <attacks>
        <attack script="custom/firecircle.lua" interval="10000"  chance="50" min="-400" max="-500"/>
        <attack name="fire" interval="2000" chance="100" range="7" min="-30" max="-50">
            <attribute key="shootEffect" value="fire"/>
            <attribute key="areaEffect" value="yellowspark"/>
        </attack>
    </attacks>

this will ignore what i wrote in the first line and use min max values from the second line.

    setCombatFormula(fireCircle[k], COMBAT_FORMULA_DAMAGE, -600, -700, -800, -900)

using this in the spell file will only work when players cast it.
How can I set the spell damage correctly when monsters use it?

 

[Tufte]

halp