CC Not showing up in CAS

I have a similar problem to this - I downloaded an edited version of a Spa Day hair - I spent ages searching for it in CAS despite putting the package file in 'Mods' but to no avail. I went back to the creator's site and she said it required Spa Day, so I thought 'Ah, okay'. But then, as I was playing, I saw a townie with that exact hair.. even though it is nowhere to be found in CAS. I've had this problem before - such as when I downloaded a jacket that won't appear in any of the clothing categories but will appear if I randomize my Sim and has appeared on random townies, so it must exist somewhere in the game..

Any solutions?