Once it's connected to your home WLAN then when you go to the Web portal Device List on a PC/Mac browser, you should see a green banner indicating that an unregistered device was found. Follow the onscreen instructions to register it to your account.
The iOS app doesn't yet support this registration mode so that's why it's not showing up there.
Please double check that it's really not waiting to be registered at the web site.
Are you 100% sure it's connected to your home network? If not, you will need to reset the plug by holding the top button down for about 10 seconds then releasing. It will reboot and you'll have to connect directly to its AJ_OpenWrt:xx.xx.xx.xx.xx.xx SSID to go through the web setup again.
Can you find its IP address either using some tool like Fing http://www.overlooksoft.com/fing or your router's DHCP Clients List (if it has one)? And then connect using web browser to that address. It should be the same view as connecting to it directly was. That will at least prove it's on your LAN.