You can configure a site-to-site VPN between those sites.
The thing is that the router will work (as long as having an encryption IOS), but you should terminate the tunnel on another router or Firewall or VPN endpoint device on the other end (the 3560 is no good for VPN endpoint).
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...