What is your goal for the IP Passthrough utillity?
If your goal involves anything to do with remote access to the Jetpack then you need to focus on the VZW NAT Firewall configuration first. Anything you attempt to do remotely will be blocked by the NAT first.
Work arounds to the NAT firewall are:
1. Setup an VPN connection to your local devices, setup the same VPN for the remote device, view everythign over the VPN
2. Upgrade to a Verizon 4GLTE Internet Installed package where public IPs are provided by default
3. Pay $500 to purchase a public IP on an enterprise VZW account
4. Switch providers to one that offers public IP services for less than VZW
I don't intend to do anything that would require remote access to the device. My goal is to have a more reliable experience using the unit with my PFSense router, and putting the unit in IPPT mode would give me the added benefit of reduced configuration complexity since I don't have a separate web interface to manage and secure for the 192.168.32.2 (mbb.vzw.com) portal.