StrTr() locale (?) problem

[Lehmi]

Well the function works fine on my home server which has the newest PHP version, but on the server it's supposed to work (using PHP 4.4.1) it doesn't.
(On that server default_charset has no value.)
On that server I can't StrToLower characters like ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ. Can any1 tell me why and how to solve this?

[Lehmi]

I've further isolated the problem. Edited the first post accordingly.

[laserlight]

Well, there is the [man]setlocale/man function... you could experiment.

[Lehmi]

Well I did use that to set the same locale as on my home server but that didn't change anything.