Charset Problem

I am virtualmin user from Turkey. Turkish language requires utf-8 or iso-8859-9 charset for characters like ‘ç, ğ, ı, ş’. I tried to change usermin’s charset to utf-8 and iso-8859-9, however, still there is error on sender’s name and title’s on mail that are sent by usermin. Can you please help me?

check this: