I also currently don't have a airsight but have foscams which email the IP each time they reconnect to the internet.
they also allow connection to no-ip a free DNNS service.
Ispy is a viewing/capture software it isn't a solution for those unable to have a constant IP which a DNNS works around.
I've never looked into the firmware files or the web UI files, both work together for connections.
Since my programing skills are limited I also don't plan on looking into it.
I have thought about writing a small app that would email users when their IP changed however that would require a PC running 24/7 which many don't wish to use.