We have a Vigor 3900

We have to VPN to a communications provider which requires the network to be on the same public network as the Gateway.

I would like to set this up so that the network address gets NAT to the our internal private network. so the settings are as:

(Private LAN) (Public Network) (Our Gateway) (Coms Provider Gateway) (coms Network)
10.10.10.20/32 94.67.81.43 94.67.81.100 78.45.23.45 78.45.23.40
==========NAT======== ================== ======site-to-site vpn================= = ===========================

The site to site VPN is up. However, when traffic is sent from 10.10.10.20, the coms network is seeing that address and not 94.67.81.43 (i.e. the address is not masqueraded), so communication is failing. We have set the 94.67.81.43 address to DMZ to 10.10.10.20 - What else is missing?

Thanks

James Den Kaat