Maybe install timezone utility? Just a guess..

-ipkg update
-ipkg install tz

-Goto the /opt/share/zoneinfo folder and find
your timezone location. Copy this location to the
folder /etc/localtime. e.g.:
cp /opt/share/zoneinfo/Europe/Amsterdam /etc/localtime

-Open '/usr/local/.files' and add this line:
/etc/localtime

-To make the change permanent, save it to flash:
flashfs save && flashfs commit && flashfs enable

-Restart Samba