I use wvdial in order to connect to the internet using a cdma usb modem that isn't detected by the nm-applet.
However, once I've connected, gnome and other gnome applications don't seem able to determine that I am connected to the internet. (e.g. empathy, ubuntu one remain offline, firefox "work offline" has to be disabled manually)
The desired effect is: I connect via wvdial and gnome detects this and enables everything appropriately.