[msmtp-users] msmtp 1.4.18-2 utf-8 problems

[msmtp@...211...]

Hello,

I have problems with emails send from php via a msmtp (1.4.18-2) google 
account to a gmx adress.
They have a wrong encoded subject, leading my local amavis to say 
"X-Amavis-Alert: BAD HEADER SECTION, Non-encoded 8-bit data (char E4 
hex):	Subject: Best\344tigung Ihres ko[...]"
The content type used is "text/html; charset=UTF-8".

If I try to use mail() with user www-data, german umlaute are wrong too.

The only thing working right seems to be with emails send by cron (root).

I don't know wether this is about msmtp or my locale settings - I'm no 
expert in these things, but maybe one of you could lead me to the right 
track?
Cheers
Frisco