1120 Secure Access Control System (CSACS 1120) comes with preloaded version 5.x and on the other side you have ACS windows CD for version 184.108.40.206 so they both have different ACSs version. There is no point running two different version running in the same network because that would not allow you to do replication or syncronization. Also both have different architecture and functionality.
I think you would be required a Recovery DVD of ACS version 4.2 so that you can downgrade the 1120 to 4.2 and use one as primary and other as secondary or backup ACS.
Why we have only option to downgrade because ACS windows 4.2 can not be upgraded to 5.x. You always have an option to migrate because 5.x only supports linux OS.
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...