I beg to differ Richard,
my BY modem is connected via a standard (straight) 5e patch cable to my Belkin wireless router - and the latter is connected by another patch cable to the main PC - been working 100% for 2 years now.
So unless Linksys say otherwise I'd say the setup originally posted by aiglon sounds good to me.
Aiglon, do you have the motorola modem or something else?
btw you will have to spoof/clone the MAC address from the main PC - 'cause that's what BY use to know you're a legit customer -- PPPoE not required. That should be in the instructions from the manufacturer.
Good luck!
amofw