set the time and save it to the RTC HW

To set the system clock use the date command.

from "http://developer.axis.com/wiki/doku.php?id=faq" article,

date MMDDHHMMYYYY

Where MM=Month, DD=Day, HH=Hour, MM=Minute, and YY=Year

To permanently store the system clock in the RTC chip just type the following command

hwclock -w

This works with busybox.