Snow Leopard DNS issue

Trouble with DNS when connecting using Mac VPN client.

Our VPN access is setup on a Cisco ASA 5510 firewall. When using Snow Leopard's built-tin VPN client, DNS is not being pulled correctly from the firewall. It connects fine, ssh/telnet and browsing to specific IP addresses works, but DNS does not. VPN connections via Cisco VPN client (Mac and Windows) going through firewall is pulling DNS from 10.9.10.191 correctly. VPN connections via built-in Mac OS VPN client using local IP gateway for DNS and not pulling from 10.9.10.191. Any suggestions? Is this a problem on the SL end of something in the firewall settings? I suspect it is a built-in VPN client issue on the Mac since it works fine using the Cisco VPN client in Windows and Mac OS X. Thanks for any help.