subject in big5 characters of an email can't be read in Lotus Notes

I have sent an email using mail function in which the subject and email body have charset=big5. Customers with outlook express can read the big5 chinese characters without any trouble. However, people who read their emails from Lotus Notes complain that they cannot read the subject. But, they can read the email body because I have set charset in the header: $mailHeader="From: blah@blah.com\r\nContent-type: text/plain; charset=big5\r\n" ; My mail statement looks like the following: mail($mailTo, $mailSubject, $mailBody, $mailHeader) ; where $mailSubject and $mailBody are both big5 char. Is there a way I can set $mailSubject charset=big5? Thanks for your help Ellen __________________________________________________ Do You Yahoo!? Yahoo! Finance - Get real-time stock quotes http://finance.yahoo.com