The reason this is happing is that your client isn't getting NetBios updates. In a NT network you can use a WINS server to solve this problem. The F&PS works because the local systems starts it's own WINS process.
Simple solution add a WINS server to your network and configure the client to use the WINS server.
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...