Defining an Ethernet Interface on USB

Hi,

I have an eth0 interface linked to the ethernet NIC and I would like to define an eth1 for the USB.

I found some information on the LDP link http://www.tldp.org/HOWTO/Motorola-Surfboard-Modem/usb.html, but refers to a Red Hat installation and to some configuration files (/etc/network/interfaces) that do not exist with the SuSE.

I would like to understand how you can define in SuSE an additional ethernet interface and how you specify that it must be associated to the USB device.

Thank you for your help

Mario Pesce