The link given will definitely work however you would not be able to select access based on the AD group, if that is what you need to achieve and you have ASA version 8.0 you can work Cut-Through-Proxy together with DAP.
Using Cut-Trough-Proxy with a standard authentication server will only allow or reject depending on the authentication result, but any user within your AD schema will be able to get internet access. If you need to restrict this based o Windows Groups as well your best shot is Cut-Through-Proxy with DAP and LDAP:
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...