tModLoader How to make an item classify as a custom damage class item.

[Kyneptic]

Sorry if that title is confusing or whatever, but i'll explain it here.

usingTerraria.ID;
usingMicrosoft.Xna.Framework;
usingTerraria;
usingTerraria.ModLoader;

namespaceMystica.Items.Weapons
{
publicclassMagnoxGreatblade : SpiritItem
{
publicoverridevoidSetStaticDefaults()
{
DisplayName.SetDefault("Magnox Greatblade");
Tooltip.SetDefault("");
}
publicoverridevoidSetDefaults()
{
item.damage=38;
item.width=10;
item.height=10;
item.useTime=25;
item.useAnimation=25;
item.useStyle=1;
item.knockBack=4;
item.value=0;
item.rare=3;
item.UseSound=SoundID.Item1;
item.autoReuse=true;
item.melee=false;
item.ranged=false;
item.thrown=false;
item.summon=false;
}

publicoverridevoidAddRecipes()
{
ModReciperecipe=newModRecipe(mod);
recipe.AddIngredient(mod, "MagnoxBar", 10);
recipe.AddTile(mod.TileType("MysticForge"));
recipe.SetResult(this);
recipe.AddRecipe();
}
}
}

This weapon is a spirit weapon, but it wont get buffed from items that buff spirit damage. Not armor, or accessory. And I believe it would be a problem with not actually classifying as a spirit weapon. Is there some sort of item.spiritDamage thing I can do? Thanks in advance.