You also have to rename everything inside the .ora of the dialog.blacksmith layer files correspondly.
And if u want to sell a artifact that wasn't available before, then open heroes4.h4r and choose any item that was sold before (like Mages_Staff) in the layers.dialog.blacksmith and save it with the name of the new artifact. And then u add that to your equi.h4r
Also change the costs of artifact in the table.