[ZendTo] Accentuated characters doesn't show correctly in mails sent by zendto v5

[Francis]

Hello,

I just installed the new zendto v5. Thank you for the great work. The
translations are very welcomed!

I found that mails sent in french don't show accents (it shows question
mark instead). Even if I have 'UTF-8' set in preferences.php for the
SMTPcharset variable, zendto send the mail as us-ascii.

Extract of the mail:
Content-Type: text/plain; charset=us-ascii
Content-Type: text/html; charset=us-ascii

A little strange thing is that I have accents in my EmailSubjectTag and
that accent display correctly in the subject field. but the rest of the
subject strip the accents (the subject display as "[Dépôt] (name) a d?pos?
un fichier pour vous).

-- 
Francis
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