How to create CC of an outfit type you don't own?

I want to edit a CC septum piercing that I downloaded, I just want to make it bigger. I edited my first CC hair and it didn't work until I started from an EA hair in S4S, so I'm doing the same thing for this piercing. The original piercing uses the "Brow Ring (Right)" outfit type, but there is no EA piece I can select from that category. 

What should I start from? And is it possible to edit the original package? When I tried that with the hair, it didn't end up in-game.