Is it possible for you to change the pool of IP Addresses to something other than your internal network. Based upon your symptoms, it looks like the ASA is getting the return traffic and simply drops the packet because it has an inside ip addresses that falls within the 10.0.0.x/24 range.
Try changing the pool to a different subnet, reconfigure the NAT 0, make sure that the internal networks know that they need to send the traffic back to the ASA for the VPN Client Pool and give it a shot. Let me know how it goes.
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...