First of all in solaris its ifconfig -a .. and you wont find the interface in ifconfig o/p until you plumb the interface .. if its solaris 10 onwards you can user dladm command. Else in solaris 9 you can see in /etc/path_to_inst
That is the expected behavior. You need to configure the OS to add these interfaces.
ifconfig -a plumb
ifconfig -a
Then create /etc/hostname.xxx for each interface you want to be plumbed at next boot, each file containing the required IP address. xxx being the interface name (eg. qfe0, qfe1, ...)
Beyond the fact it's Solaris 9 so dladm isn't available as DukeNuke2 already point out, what's wrong with plumbing all interfaces ?
This is incorrect. The interface doesn't automagically configure itself with DHCP. Moreover, it will will be lost at next reboot if nothing is done to avoid that ...