Letter substitution with "-" or "_". NOT "?"(question mark)

My soulseek doesn't show some of those non-English alphabets (Spanish or French, etc) I assume it's because my Windows system is Korean version. It substitutes those letters to "?"(question marks), which, of course, make the file impossible to download. If you can change the substitution letter to "-" or "_" It would be great. Even if that is not something you can fix, it's okay.