there is usually a script that starts up during boot that you (as a admin) can edit so as to add commands to run at the last stage of boot process.
You can simply add the same commands that you normally type to bring the nic up...
i.e. # ifconfig eth0 up
Unsure where this is in SUSE... but im sure someone can help (or you may already know even).
In slackware it is /etc/rc.d/rc.local
in ubuntu is /etc/init.d/rcS
good luck!