As with most enterprise two-factor authentication deployments, Computer Port used Radius. In this example, they pointed the Cisco VPN directly to WiKID, but they also could have routed the authentications through NPS. In addition to this screencast version, please see this tutorial on adding two-factor authentication via the ADSM 6.4 and this one using the ASA console.

Remember: the WiKID Strong Authentication Enterprise server is free for up to five users.