locale and german umlauts

Hi!

I know that someone had problems before with the upper() and lower() 
functions with german umlauts or polish signs. So could please anyone who 
solved the problem tell me what to do to get the upper() and lower() 
functions working properly?

I compiled postgres 7.1.2 with 
./configure \
--with-tcl \
--with-java \
--enable-locale
make && make install
initdb -D /usr/local/pgsql/data

I set 

export LC_CTYPE=de_DE.ISO8859-1
export LC_COLLATE=de_DE.ISO8859-1

and make a database with 

createdb test.

Is there something obvious I'm doing wrong?

Thanks!