Audio Systems: home theater cabling, yamaha rx v661, fly by night

Question
I have a 50" Samsung (HP5033), and a Yamaha RX-V661 receiver.  No problem with the DVD and CD hook-up.  I get the surround sound with both of the above.  However, it is my understanding that i should also be able to get the surround sound through the reeceiver from regualr tv broadcasts as well.  The tv is hooked up to cqble through an HDMI box utilizing a HDMI cable.  The manual is very vague and does not detail the wiring needed.

Answer
Surround sound whether it be encoded Dolby, DTS or some version of descrete requires either processing or matrixing of some kind. There are too many flavors for most receivers to automatically decode. More that likely the Yamaha is factory shipped with  the mode control set to sense and matrix a signal from CD & DVD inputs. The possibilities are endless.I am not familiar enough with consumer A/V to know that receiver without doing the research myself.  It is virtually impossible for anyone to evaluate the actual condition without either knowing the precise hookup and the exact configuration options for the Yamaha. I recommend that you contact Yamaha customer support. This is not a fly by night company and even if it takes awhile they will be the most qualified to answer you.