If your ISP uses pppoe to give you the address.. ie, you need to authenticate onto their network, then you may need to add something like the following:
vpdn group GRP_NAME request dialout pppoe
vpdn group GRP_NAME localname username@isp
vpdn group GRP_NAME ppp authentication chap
vpdn username username@isp password MY_PASSWORD
ip address outside pppoe setroute
Of course, if the ISP uses DHCP, ignore this posting :)
