Thank you very much for the reply.
I have downloaded the latest xsl file, pd4ml_demo.jar and ss_css2.jar.
Then I have tried to convert the dxl file to a PDF file using the command line tool.

Here is the HTML copied from the console by -dumphtml:

The Chinese work are correct.

And here is the console of using the command line tool:

I have specified the fonts. I have tried specified the correct fonts and all fonts using the Chinese supported fonts. Both result still got the wrong characters of the filenames of the attachments in the PDF file.

What should I do next?
Thank a lot.