Language encoding setup.

Guys,

When I upgraded my WWF forum from 6.X to 7.01, I tried to add a line as "charset=gb2312" in one file (Can't remember the file name).

After that, Chinse language is working well on my forum, also the email notification are GB2312 coded, emails displayed in Chinese directly. Now, I upgraded the forum from 7.01 to 7.51, I found that the good days are gone, the email notification from the forum are coded in "West European" Language and I have to change the encoding to read Chinese every time.

Is there any suggestion that which file and where I should add this line: "charset=gb2312"?

Thank you!