The Dish User Manual tells you to try codes and search them by trying to Power Off your receiver. I found out that the Onkyo codes they list don't Power Off my Onkyo receiver, but they do Power it On, Control Volume, and Muting. So if you are searching, you might want to try and Power On instead of Power Off.
This also works for my Harman Kardon AVR 510, using the listed code (672). Thank you, Building.