How to change encoding on iPad or iPhone mail? I use Mac OS X, iPad and iPhone.

There are occasions when I receive mails send from people who uses Outlook written in different asian languages (Japanese, Korean, Chineses etc.). I could read them OK on my Mac, but if I reply to any of them, other people would sometime receive gibberish characters.  On my Mac OS X's Mail.app, I have to set each email I reply to encode in UTF-8 Unicode to make sure the receiver can read it (note: if I am compose a new email then without setting the encoding, the receiver read them ok. Only on replying their email they receive gibberish).

But on my iPhone and iPad I cannot find how to set the encoding of the email. How to solve it? That is, when I reply email with asian characters, how can I ensure they do not changed to gibberish?
I seldom use Unicode characters but, as far as I can tell, it seems the Mail.app sets the encoding based on what you're typing. So if you don't type any Unicode characters it will asume a different encoding (based on the language defined in your device).

Try to add an Unicode character to your replies as a workaround (maybe in your signature)!