Ability: Spell Damage Reduction (but not immunity)

I have been trying to create an ability for magic/spell damage reduction.

But all that I am coming up with is nothing, or resistant to all magic.

What I though was my best shot for creating this ability was to take the stock item "Spell Damage Reduction", mark it as an ability, change the icon and we would be done. After doing this and giving this ability to a creep, I never see the icon at the specified location (yes, x/y are correct).

I have also tested to see if the ability was there and not seen. No go there. Blood Mage still cooks the creep.

I have matched the Spell Damage Reduction Ability (based off the item) side by side with other abilities looking to see if I forgot anything and I can't see a thing.

Anyone have any tips on how to make an ability to reduce just magical damage?

Thxs in advance.

but it seems spell damage does work now .. and of course Murphy's Law applies here.

Just can't get the icon to show up as an ability.

Spell Resistance is like that - the icon wont show up. You need to trigger it if you want an icon to show, or if it isn't a hero with this ability, just give the unit a dud ability with the icon .