SIP From header for E911 Calls with Twilio

I have an old Fonality server running Asterisk 1.6. I know, we’re trying to get rid of it…

If you’re not familiar with Fonality, it’s more or less just a GUI for Asterisk. We are moving to Twilio as our VOIP provider but they require a E.164 formatted number in the SIP From header when placing 911 calls. This is a problem as Fonality does not do this and does not offer any way to configure this.

I’m familiar with Asterisk configuration as I’ve set up an Asterisk server before, but I can’t figure out what change I need to make to make this work. We are completely US-based, so I would simply need to add “+1” in front of the current From header.

Appreciate the help!