I'd be rather surprised if ISO8859_1 is the source of your problem. I know
nothing about German, but Norwegian characters (æøå) work brilliantly in
this character set (and I've seen messages indicating it being used by
other European languages as well).

I suggest you

a) check that the field(s) in question is defined with this character set

b) check that you've set up this character set with the components you are
using (in IBO, this will be in your TIB_Connection, don't know about IBX or
BDE)

HTH,
Set