This would only be useful for those using PRIs or VoIP (my case) where you can set your outbound callerid programatically. This applies to 3.1.6 and will use whatever the user puts in the 'Fax Number' field on their settings page for the number and the 'Your Name' field for the outbound callerid. Use in conjunction with ModemSetOriginCmd in your modem config file, using %d as a macro for the number and %s for the name. Example for IAXModem is:
ModemSetOriginCmd: "AT+VSID=\"%s\",\"%d\""
To implement this in HylaFAX, you'd have to use a jobcontrol script and the ModemDialCmd setting:
ModemDialCmd: "AT+iO<number>;DT%s"
The script would look up which user sent the fax, and substitute <number> with the user's fax number. For PRIs, the outbound callerid must be numeric (ie: no special characters).
Also, HylaFAX sendfax options "-e" and "-u" don't exist. They're not needed anyway since the job control script would do everything.