Comcast box NRG110 IR codes not working

I have been researching this for awhile now and I can not get anything to work.  I am trying to get our company digital signage setup which includes using Comcast live TV input via HDMI out and into our digital signage applicance  (Brightstor) 

We would like to have to option to use our signage box to send IR codes to the cable box to change the channel on the reciever.    Unfortunatally, the Comcast box we have the NRG110 does not play well with sending HEX pronto codes to it. I have read and tried 100s of code and it will send anyting to that box . it seems its a common issue with these boxes

I called comcast to see if there was any way to upgrade to a diffrent box to make it easier to program these codes, but I was told that was not an option as that is the only box i could use.

any thoughts?