I have two nics, eth0 is set up with dhcp for my cable modem,
and eth1 is set up manually for my file server.
Both of these were installed before installation, however the suse live eval cd did a good job configuring them, so i dont see why you cant do what you need to.
if this is what you need to do, just make sure you know which one is which and configure as i have.
If you need more just ask