Are you substituting because (1) you can't find Golden Naked Oats to use or because (2) Golden Naked Oats is not in the Beersmith ingredient list? If it's number 2 you can add ingredients yourself into the ingredient list. You can go to the Simpson's website and look up the profile of the malt and just create a new entry.
You can add it by going to the add fermentables tab. In the bottom right hand corner select the "Fermentable add-ons". There you can select grains from different suppliers that are not preloaded. Select simpson and add. This will add the golden naked oats to your list.