[Typo3] UTF-8 in Mails

[Robert Markula]

I'm curious; in my TS I enabled UTF-8, but Mails don't get send with the 
right header - actually the header responsible for setting the right 
charset and encoding doesn't get sent at all.
With this TS setup

# Setting the encoding for outgoing e-mails
   config.notification_email_encoding = base64
   config.notification_email_charset = UTF-8

the header should look like this:

Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: base64

but these two lines are missing in the header of sent mails.
As a result, all mails are displayed as ISO-8859-1, which messes up all 
german umlauts, because the message body *is* encoded in UTF-8. It just 
isn't present in the header.

This affects all extensions that use htmlmail class 
(class.t3lib_htmlmail.php).
I'm using Typo3 3.8. ForceCharset is set to UTF-8.

Any advice?

Ro