I just read the Audioholics review on this receiver yesterday, and I believe that you need to tell the receiver what type of display output you're using to send the On Screen Display in the proper format. To quote the review:
To get the OSD running, the first step is to consider the video connection used for the main monitor: HDMI, component, S-video, or composite video, and set the output mode using the switch labeled HDMI OUT under the front flap. Repeatedly pressing this button will cycle through these alternates while the TX-SR805’s front LED display shows the current setting if the default does not match the current monitor connection.
Other than that, how do you like the receiver?
Mike