Configuration of the outside interface for PPPOE configuration example,
sanjose is the username and cisco123 is the password provided by the ISP:
ip address outside pppoe setroute
! --- Specify PPPOE as the method to obtain the address for the outside interface.
vpdn group xyz request dialout pppoe
vpdn group xyz localname sanjose
! --- Note that the localname (sanjose) is the username the ISP provided.
vpdn group xyz ppp authentication pap
vpdn username sanjose password cisco123
! --- Note that the password (cisco123) is the password the ISP provided.
Refer this link:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_62/config/pixclnt.htm#40037