Using the letter "ß" in the keyword search

In Germany we had the letter "ß" like "ss" in other states . If I use this letter in a keyword tag -  "weiß" for example, there ist no result in the keyword search results. If i rewrite it from "ß" to "ss" the search works. Is there any setting to use the german "ß" in search tags? The other umlauts does work for example "ä" or "ü" .