/opt/local/etc/ports/variants.conf doesn't work.

Hi, I want to set my default variants in /opt/local/etc/ports/variants.conf, but it seems not to work.. i just set, 12 # Example: 13 # +ipv6 +no_x11 14 +puredarwin +ncurses +darwin -x86 +multibyte like above, but, when I try to compile vim70, vim70 doesn't accept multibyte variants. what can I do? thanks!