I assume that what you mean is that the preshared keys are encrypted/hidden so that you only see xxx for the key when looking at the config, and that the xxx gets transferred not the valid key.
If my understanding is right then I suggest that you try this: on the concentrator management interface under Administration select Access Rights; then select Access Settings. On that screen is a set of options for Config File Encryption (encrypt with RC4, None, or encrypt with DES). Select the option of none and click apply. Then transfer your config again. I believe that you will find that the preshared key transfers this way. Be sure to go back and select the encryption option that was previously used after the transfer is completed.
If my understanding was not correct and my suggestion did not resolve your issue, perhaps you can clarify the situation.
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...