Trying to show a necklace accessory over certain shirts

So I’m having this problem where I have a cc scarf and It’s classified as a necklace so it wont show on certain clothing, even though it says it’s on there, but it just appears to not be there, and it isn’t a mesh problem either. I’ve found how to change this, but I donno where to go to do this. 

can somebody give me a tutorial on how to edit regional maps on certain clothings (one of them is a custom content and I donno how to put it on S4S.) I’m really new to this software and I just want to make it so this scarf can go over a certain top that doesn’t allow necklaces, and how to make it work on my game as well!

thanks!