how to control charset of directory listing via .htaccess?

I've enabled directory listing of a folder under public_html, by adding: Options +Indexes in the .htaccess file. However, some files are not listed correctly by default, as some filenames are in Chinese (UTF-8 encoded). I can see the filenames if the change the browser's charset encoding to UTF-8. How can I let the browser see the filenames in UTF-8 by default? Is there a parameter to add in the .htaccess? I tried adding: AddDefaultCharset utf-8 in the .htaccess file but it does not change anything. Thanks~