Static IP from ISP with a router in-between to XG firewall

Question

I have a XG firewall and the isp is giving us a static ip for our main Internet Connection. 
 They insist that we have to use their router before we connect the internet to the XG firewall. 
 If i want to use the static ip to have a site to site ipsec vpn what settings should i look into on the ISP provided router? 
 Basically i want to use the static ip with the XG firewall without having to setup port forwarding and other things like that, is this possible? 
 For example if i set up WAN access on the XG firewall for my static ip i should be able to access the firewall. 
 Thanks for the help.

jprusch · Answer

Hello Tom, 
 this is sometimes called an "exposed host" on the ISP router / modem. 
 That means any service and any packets are passed through to that particular internal IP.