It is a minor hack, but it works. I tested it.
I usually test whatever I share, the only exception is when I am giving ideas while away from my computer.
If you want it to still count the Strength die, here is how to do it.
For the "Weapon Die" field, put "None". Leave "Special Damage" blank.
Make an Eval Script. I tested it at Traits 5000, which allows for mods to Strength to already exist.
Code:
var strVal as number
var damage as string
strVal = #trait[attrStr]
damage = "nothing"
if (strVal < 2) then
damage = "2d4-2"
elseif (strVal = 2) then
damage = "Str + 2d4"
elseif (strVal = 3) then
damage = "Str + 2d6"
elseif (strVal = 4) then
damage = "Str + 2d8"
elseif (strVal = 5) then
damage = "Str + 2d10"
else
damage = "Str + 2d12"
endif
this.field[wpDamage].text = damage