You can do it in PIX V6 but recommendation is against. In V7 is not supportecd at all, from the Reldease notes :-
If you share the Stateful Failover update link with a link for regular traffic such as your inside interface, you must change your configuration before upgrading. Do not upgrade until you have corrected your configuration, as this is not a supported configuration and Version 7.2(2) treats the LAN failover and Stateful Failover update interfaces as special interfaces. If you upgrade to Version 7.2(2) with a configuration that shares an interface for both regular traffic and the Stateful Failover updates, configuration related to the regular traffic interface will be lost after the upgrade. The lost configuration may prevent you from connecting to the security appliance over the network.
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...