In your network card properties, set a static IP of 10.0.0.1, netmask 255.255.255.0, with the gateway & dns blank. That will make sure that your computer will not get a DHCP IP from the 6520.
Then just simply set up a PPPoE connection on your computer, be it via Windows XP's PPPoE connectoid, RASPPPoE, Access Manager, etc., or connect your own router and configure it according to the instructions supplied by the router manufacturer.
Note: You do not need to reconfigure the 6520 in order for it to function in bridge mode.
See this thread for more information: /forum/remark,13518656