Please see 5.c. of "How do I manage my built in WiFi modem?" in this PDF. Please make sure to uncheck SSID Enable, and click Save Settings, for each radio individually, as if you uncheck all four, then click Save Settings, the settings won't hold. i.e. Uncheck SSID Enable for the 2.4Ghz radio, then click Save Settings, and then do the same for each of the other three, individually.
Hope this helps.
Edit: In addition, you should probably uncheck the two Frequency Band boxes in the Advanced settings, as I believe this turns off the WiFi all together, and not just the broadcast of the SSID. This way, your own router will receive no interference from the HughesNet WiFi. Make sure to click Save Settings, at the bottom of the page, after unchecking these.