Default encoding on Mail.app

I’d like to set Thai to be my default language in Mail.app but I couldn’t find where to set it in Mail preference . So I did a little google and found the solution is very simple. In my case, Thai can use either Windows-874 and TIS-620. Here is the command that I run on Terminal and it works pretty well.

defaults write com.apple.mail NSPreferredMailCharset “TIS-620”