Setup VPN for FVS318V3 with WAN port on a privet ip address

Hi

Internet WAN port for Netgear VPN Firewall FVS318V3 is connected to LAN port for Netgear Wireless cable Modem CG814WG.


LAN IP address for Netgear Wireless cable Modem CG814WG is static address 10.10.0.1/24,,,and WAN ip address is dynamic by ISP.

and DHCP is on for the range 10.10.0.30 to 10.10.0.150,,,,,,,,

Internet port (not LAN ports) IP address for Netgear VPN Firewall FVS318V3 is static address :
10.10.0.20/24
Obviously gateway would be 10.10.0.1

LAN IP address for Netgear VPN Firewall FVS318V3 is 192.168.0.1/24

And DHCP is on for the range 192.168.0.1 to 192.168.0.150

I have got no problem to surfing the net (i.e scenario above is working without any problem), but I am planning to setup a VPN ,,,,,

Which public ip address should I use if want to setup the VPN ?

If I use the dynamic WAN ip address (or DyDNS.com) for the Netgear Wireless cable Modem CG814WG, do I need to NAT that to the 10.10.0.20/24 ? ?

Thanks