You must register your WeMo device's hardware address before it can connect to the Stanford network.
The hardware address (aka MAC address) for most WeMo devices (Mini Smart Plug, Smart Switch), is usually printed on the back of the device (front for the Wemo® Light Switch). However, the MAC address the network uses is one digit higher that the one printed on the sticker. (See "Why two MAC addresses" (belkin.com).)
Once you've located the hardware address for your device, you can register it following the instructions for "Connecting a device that does not have a web browser". Remember to increase the last digit by one increment!