I want to access our internal LAN from a remote location. The LAN will be protected by the RouteFinder SOHO firewall/gateway with Nat. The remote users are also behind a NAT/DSL gateway(w/IPSec pass-thru only).

You can setup a VPN by installing two RF550VPN, one at the head office and one at the remote office. All the workstations behind the remote office will able to access all the LAN resources behind the head office over the VPN tunnel. No need to use any IPsec client software on the workstations, RF550VPN will handle all the VPN traffics between the two LAN.