IDMessage und Umlaute in der Emailadresse

[gaisser]

Das funktioniert leider auch nicht, was mach ich falsch?

Delphi-Quellcode:

    IdMessage.Subject := MailText;
    IdMessage.From.Address := StringReplace(Turi.UnicodeToIDNA(frmSetup.Email.Text),'xn--','',[rfReplaceAll]);
    IdMessage.From.Name := EdName.Text;
    if EdReplayTo.Text <> '' then
      IdMessage.ReplyTo.EMailAddresses := StringReplace(Turi.UnicodeToIDNA(EdReplayTo.Text),'xn--','',[rfReplaceAll])
    else
      IdMessage.ReplyTo.EMailAddresses := StringReplace(Turi.UnicodeToIDNA(frmSetup.Email.Text),'xn--','',[rfReplaceAll]);;
    IdMessage.CharSet := CbCharSet.Text;
    IdMessage.Recipients.EMailAddresses :=  StringReplace(Turi.UnicodeToIDNA(empfaenger),'xn--','',[rfReplaceAll]);
    if BCC <> '' then
      IdMessage.BccList.EMailAddresses := StringReplace(Turi.UnicodeToIDNA(BCC),'xn--','',[rfReplaceAll]);