Lesson of the Day: BGP is not supported on ASA
Juniper SSG using ScreenOS are featured rich but it can also become internet facing device even if you need dual homing, as it supports BGP
Beside other feaures Cisco ASA with Linux kernell left behinf in routing protocol support. Till now BGP is still unsupported on ASA platform.
SSG support RIPv1/2, OSPF, BGP, Frame Relay, Multilink Frame Relay, PPP, Multilink PPP, HDLC and ASA only RIPv1/2, OSPF.