I think it is a good idea to add more info (ttyIAX port number used for example) and more config options (codecs, registry time) in the virtual faxes page. When you create a virtual fax in Elastix, it creates a /etc/iaxmodem/iaxmodem-cfg.ttyIAX* file with the iaxmodem config, and by default it selects slinear codec (here in Spain we use ulaw) and sets the registry time to 300 seconds. I get constant complaints in the asterisk logs about this. I have to manually change it to 60 seconds, reboot, and then I stop receiving these messages. I have been testing faxing lately. I use avantfax, but create the virtual fax with your web interface. I hope you stop working so hard in your fax implementation: Avantfax is lovely! You should speak with the developers and try to focus to improve Avantfax and integrate it in Elastix.