Which settings for German Umlauts?

Which system settings do I need in order to get the German Umlauts + "ß" converted?

**ä → ae
ö → oe
ü → ue
ß → ss**

I guess it has to be a combination of these three:

```
filesluggy.charset_iconv
filesluggy.enc
filesluggy.regexp
```

For a file named `schönes Bild.jpg` i get an Unknown Error (the file uploads, but the filename does not get altered at all).