HT S3500 no sound center/sub

Connected receiver to directv box with HDMI per diagram
Connected receiver to Hitachi HDTV with HDMI per diagram
All speakers connected per instructions
No DVD or other component connected
Only getting sound from L/R speakers, not from center or subwoofer

I am a newbie. Am I missing something obvious? Thanks.

In regards to your issue- it would possibly be more effective to contact our Product Support Dept for further assistance with this specific issue via our phone number and hours of operation below. We would like to speak with you and work to troubleshoot and resolve your issue, with you having access to your unit, as prompt as possible. Product Support is here to assist you from 9am to 8pm Mon. to Fri. and Sat. and Sun. from 10am to 4pm eastern std. time.

Thanks,

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