cfmail problem

Hi,

I have a html file with the charset equal to "big5-HKSCS", when I using the cffile to read the file and using the cfmail to send out the html file, all the Hong Kong Supplementary Character Set (HKSCS) fonts becomes "?" in the email. I have try to print out the content read by the cffile, it can correctly display all the characters. How can I solve the problem?

Server configuration as belows:
Windows 2003 with HKSCS character set installed
Coldfusion MX 7 Enterprise

Thanks!
thkl