Do you have syslog enabled? If yes, what log says about icmp.
Remember by default, ICMP won't be inspected. Therefore, you have to either permit echo-reply on outside interface or enable icmp inspection. Since you have already configured "permit any" on outside interface, you should be able to ping.
If packet was dropped by ASA, you should see something in log or by enable "debug icmp trace 255".
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...