I thought that ExtendScript as high level programming language solve this low-level things instead of me. Stupid idea 
So I have to redesign whole file management in my project.
It can by solved only:
1) Save the filename directly into created file (eg.: filename.open("w"); file.writeln(filename.name)) and read it back.
2) Reencoded filename to Base64 string - really strange 
but could help.
3) Don't use accented characters – not acceptable for me in these days of 21. century.
Or any other idea?