There were two meshes in the file I downloaded, so four files in total (dress, key, dress mesh, and I'm presuming a key mesh). Usually if you have an outfit but no mesh, it still shows up in-game, but it defaults to a Maxis outfit when you click on it. But neither of these show up at all, mesh or no. So I'm at a loss. Were there other meshes we needed besides those packaged with the outfit?

I had the same problem as VerDeTerre. Neither the key nor the dress will show up in-game or in Bodyshop. I have all the expansion and stuff packs except the new Mansion Stuff. So I'd also be interested in finding out if it worked in-game for anyone.