It will show up but it is not easy. I took screen shots so I could explain this a long time ago, they are on another computer.
I will try and do this with words only. First thing to understand is you can't get access to any WIP or that section from your Xbox even if you are using it as a browser. You must go to BethNet on a separate device. Go to BethNet on a different device and you must sign in and that account must be linked to your Xbox. Use the link provided above and you will go to the correct page then click add to my library or favorite it, both ways work and yes you can do both.
Lets say it is too hard for you to transfer that link and you just want to search for it. If you search workshop plus you will not return any results because it is in the WIP section and is partially hidden. There is a list on the left side, scroll to the bottom and you will see WIP, add your check mark, now search again and it will show up.
You must add this mod to your library from a device that is not your XBOX to see it on your Xbox. It works a little different on PCs, but an XBOX does not see any part of the WIP section the only way for you to access that section is to already have the mod in your library, making them favorites is the best and easiest.