Sophos XG 18 - Static NAT - Having a problem creating a 1 to 1 rule

I've got a block of 5 static IP's. We'll call them 1.1.1.1 - 1.1.1.5.

By default, all objects on my LAN appear on the internet as coming from 1.1.1.1

I need my exchange server to show up as 1.1.1.2

Here's my firewall rule: On the destination network, #PORT2:1 is WAN IP 1.1.1.2

My NAT Rule:

Thank you for any assistance.