Encoding troubles

[Farmboy]

Hello,
I am running gentoo on amd64 with KDE
as DE and my LANG variable is set to de_DE@euro
which maps to the charset ISO-8859-15.

I have a website which has content in UTF-8
including links to files with german umlauts.

if I open that website in firefox and click on
the file then firefox tries to open libreoffice
but the file name it gives to libre office is encoded
in UTF-8 but the name of the file in tmp has been encoded using
the system encoding of ISO-8859-15.
So opening the file in libre office fails.

If I change the system charset to UTF-8 firefox works
but then I have troubles using eclipse because
the content of files there are encoded using ISO-8859-15
and it looks like it also tries to resolve file names
with that encoding.

Is there something I can do to make GTK apps
behave correctly no matter what system charset
i choose?

Or are these bugs of firefox and eclipse because the app developers
dont convert file names to the system locale?

Any insight in this matter would be appreciated
Thank you very much

[alex.blackbit]

I strongly suggest to use a UTF-8 locale, in your case de_DE.UTF-8.
If eclipse does not behave correctly then, search an according setting of eclipse.
To check the encoding of a file use can use file -i.
To convert existing files to a different charset/encoding there is iconv.