Can you give us a run-down of the whole process? Where the file is produced, how it's transferred, your Application definition (codepages, user exits), is it transformed on the way out of CMOD, which client are you using, is there any translation on the client side, etc, etc...
Codepages are like timezone libraries... We do our very best to avoid scratching the finely polished exterior to see the horrors just below the surface!
-JD.