[SOLVED] No Traffic to VIPs routing to Exchange server

My office recently had to switch to a wireless modem with a single public IP address. I never configured the old modem, so I'm fairly inexperienced with fortinet's systems.

The router we're using is a FortiWifi 50B, running FortiOS 3.0.  The firmware version is FortiWiFi-50B 3.00-b0668(MR6 Patch 2). Yes, it's old.

The router connects our private office network to the internet.  On our network is an exchange server to handle our email.  The email is handled by several VIP rules which route the traffic to different ports on the exchange server.

For whatever reason, Outbound email works, but I'm monitoring the VIPs and no traffic is hitting them.

I'm pretty sure it's an IP issue within the VIP configuration.  Currently for the external IP I have it set to the public IP address given by the modem.  I have also tried the internal IP address of the modem from which the router gets its connection.

I only have one IP to give to the VIPs, and in the past I think there was a separate static IP that handled the emails.  Is using only one IP for both the network and the VIPs causing a conflict?

EDIT: I got it to work.  It turns out that it was a port forwarding issue.  Our modem didn't allow traffic through the ports the VIPs needed by default.  I also had to change the IPs that the VIPs were looking for to be the IP of the modem.