Item with ability - mana cost not appearing

Level 8
Aug 18, 2008
Much like DotA and other maps I wanted to create items - with abilities, that had a mana cost to it.

So, I created a item I named Horn of the Misty Shores that upon use summons a cloud.
A cloud that makes every enemy unit inside the cloud to have a 25% chance to miss on attack.
But - and this is a big one, when I gave the item the ability, the mana cost did not appear on the item.

So I decided to ask the chat and Bonebreaker told me that one of Warcraft III's items has a mana cost and that is the Tome of Sacrifices.
Indeed it did, but this didn't help me one bit.
Since I am still as dumbfounded as when I first encounted the problem in the first place.

Long story short - how do I make the mana cost appear?
Help is very much appreciated.

Items -
Horn of the Misty Shores tooltip is not the actual one neither is the gold cost.

Oh yeah, and this is for leet.firefox :ogre_hurrhurr: