How can I changed the timezone of nios2 linux?

hi all:

I execed ntpdate on nios2-linux.It's work fine. My nios2-linux can synch net time

server. But I meet a question. My nios2-linux time zone is MST. I am not find the

"local time" file in /etc .So I copy the "local time" file in the /etc. But after exec

ntpdate, my system time still synch with MST time, not synch time with time zone of the /etc/local time file.

How can I changed the timezone of nios2 linux?

Thanks