How would I set this WAN Connection up without a router?

[SkyCatcher]

Currently using a separate firewall and router and looking to replace both with a 120G, but I'm not sure how I would go about that. Played around with the VM, but I'm still a bit confused.

We have an assigned IP from the Datacenter that the router uses (WAN 90.200.150.132/29, Gateway 90.200.150.129, LAN 60.60.100.249)

Then the firewall has Client IP addresses 60.60.100.248/29 available and uses 60.60.100.250-254, Gateway 60.60.100.249

Private Lan then uses 10.0.0.0/32

So if I start from the Private Lan then I'd create a virtual Switch and assign any ports I'd like to use the 10.0.0.0 on.

That takes care of endpoints.

The Wan, lets say port 1, would then be 90.200.150.132 with the gateway defined in the static routes? or would the WAN be 60.60.100.250-254?

In either case I need one more hop. Site-to-Site VPNs would be running on 60.60.100.250-254 customer IPs

So how would I configure the FG to 60.60.100.250 while routing out to 90.200.150.132 with its own gateway? Theres no HTTP, NAT or anything else allowed on the 90.200.150.132 network, only on the client IP pool.

TLDR: Private IP -> FG IP for VPN and Management 60.60.100.250  -> how to route that out to 90.200.150.132 with GW 90.200.150.129