RC360 not upscaling

I purchased a new HT RC360 amplifier for the sole purpose of upscaling to a new 60" LG plasma (from a 8300HD cable box--HDMI). I've read the manual, rebooted the HD box and see no difference when I choose 1080p as the output resolution on the TV screen. isn't upscaling to 1080p suppose to fill the 16:9 screen? Of course my HD channels are good in this respect and the picture is great but not when broadcasting regular, non-hd source channels. I have tried everything I could changing HDMI cables (I have many of them- different brands, all newer 1.4 types), rebooted the box, rebooted the receiver (factory reset)--nothing. Am I misunderstanding "upscaling"?

Thanks,

Hi DDKBDA,
I have an assoicate looking into this for you and will get back to you soon, thank you for your patience.

Hi DDKBDA,
What you are refering too is the aspect ratio not upscaling. Upscaling is increasing the resolution and aspect ratio is changing the picture from 4:3 to 16:9 or vice verse. Have you tried the picture adjust under the source setup to see if that works as that is the only possible way to adjust it. If that does not work then it is most likely the signal that is coming in. Thank you for contacting Product Support via our forum.