I did some experiments with connman and found that connman does not appear to know about the g_ether usb ethernet device.
When I did the following per http://www.gigamegablog.com/2012/02/06/beaglebone-linux-101-assigning-a-static-ip-address-with-connman/ it prints nothing:
cd /usr/lib/connman/test/ ./get-services
However when I plug a network cable into the ethernet (eth0) it reports information about that.
I'm still digging to find where/how the usb0 ethernet device is configured.