Save cemetery lot including custom ghosts?

[Catangi]

I deleted some of the worst-named and most-ugly ghosts from the town cemetery, and then killed some of my test sims and put their graves in the cemetery so that I would still have a lot of ghosts there. Then I decided I wanted to start a new town. I saved the cemetery lot so I wouldn't have to do the whole process over again, and then tried to place it in the new game.

It worked fine, but the only ghosts that show up are the "standard" ghosts. (The ones I deleted are still deleted.) My custom ghosts don't appear. Do I have to do something special to save them, or is this a part of the game that just doesn't work like I hoped it would?