Posso confirmar que esse problema existe. O cliente Anyconnect funcionou bem com 11.10 mas parou de trabalhar com 12.04. Truque antigo com links para bibliotecas do firefox não funciona mais. Eu acabei usando o OpenConnect.
Instalação: link Roteamento: link
Mais detalhes sobre o problema do Cisco Anyconnect:
Como você pode ver no log: o usuário conseguiu fazer o login, mas o cliente Anyconnect ainda não conseguiu estabelecer conexão vpn.
Cisco AnyConnect VPN Client (versão 2.5.3055).
state: Connecting
notice: Establishing VPN session...
notice: Checking for profile updates...
notice: Checking for product updates...
notice: Checking for customization updates...
notice: Checking for localization updates...
state: Connecting
notice: Establishing VPN session...
notice: Establishing VPN - Initiating connection...
state: Disconnecting
notice: Disconnect in progress, please wait...
state: Disconnected
notice: VPN session ended.
error: The certificate on the secure gateway is invalid. A VPN connection will not be established.
error: AnyConnect was not able to establish a connection to the specified secure gateway. Please try connecting again.
notice: Connection attempt has failed.
state: Disconnected