[Smilie]

im not 100% sure what u wanna do
but i assume u want to use the ethernet to connect a differant computer right??
from what i remember reading
u cant use both as u already pointed out
so dont think u cant have both a ethernet and USB connecting to the modem at the same time
and if u want to change to using the ethernet u need to
turn off the modem remove USB, connect ethernet
then reboot the modem

i think some1 will come along and confirm if what im saying is correct or not

Edit:
hehe beaten by 1 min :P