Due to about 99% of people saying that this didnt work for them, im rewritting the guide.
Download items.csv here. open the file.
In there will show the item entry first, then the Display ID.
It will look something like this.
20407,32841,4,1,20,0,2,Twilight Cultist Robe
underlined is the item entry.
Underlined here would be the display ID.
20407,32841,4,1,20,0,2,Twilight Cultist Robe
This goes really good for making items at WoW Vendetta - Wage Your War for your private server.