File to Mobile with external subtitle

Hello,

I’m trying to convert the avi file with external subtitle using the DVDFab
File to Mobile option. Everything works fine if I use the english
subtitle. But when I use the Japanese external subtitle file,
the converted image has only broken characters.
I tried UTF-8, Unicode, Ansi character codes with no avail.

I guess the problem can be solved if I can specifiy the unicode
font when converting the video file. But I couldn’t find any
option to change the subtitle font.

So how can I make DVDFab correctly render Japanese font
while converting the video file?

Thanks for the help.