Red Hat Linux 7.2
Apache 1.3.26
PHP 4.2.2
P3 500mhz

Web site has not only Japanese and English, but also German, French and Italian content.

Using SJIS for Japanese Encoding, ISO-8955-1 for everything else.  Internal encoding, http input and http output.

I set in php.ini to override the mail() function with mb_send_mail().

When the language was set to "Japanese" it worked fine for sending Japanese email.

When the language was set to "English" it wouldn't display western european characters such as umlauts and accents in the resulting email.  Since setting the language to "English" before calling this function is supposed to make it use ISO-8955-1, it should have displayed those characters fine, just as it did with HTTP output.

Workaround: Tell PHP not to override mail() with mb_send_mail(), and instead pass an additional header to mail() saying "'Content-Type: text/plain; charset=' . mb_internal_encoding()"