Choice of ADSL Modem to use with a netgear 318 VPN server

I am trying to get our office network to be accesible from home.

We have a netgear 318 and have set up the VPN server and I am using
VPN tracker on my mac to access it.

The problem is that it appears the the actiontec adsl modem router
that connects the firewall/vpn 318 to the WAN will only allow ipsec
pass through if it is on the client side, not into the server.

I have tried the netgear adsl modem router, but for some bizare reason
it does not work in the office, but it works first time at home!!!
hence the swap

Has anyone had experience of a simple ADSL modem router that you can
put a vpn server box behind and ipsec passthrough will work

Thanks

david