Sony TV and Sony Amp via HDMI

[Branksome2]

I have a Sony TV KDL46HX903 and a Sony A/V processor DN1010. They are connected by an HDMI cable

I also have an HTPC for HD TV and other media which connects directly to the Sony amp via HDMI.

For various reasons, I decided to make a change so that the audio from the HTPC can come via an optical TOS link rather than the HDMI. To do this, the Sony Amp requires selecting a different input option which allows me to tell the amp that the video is from the HDMI and the audio is from the optical connection. There is no change to the HDMI physical connection. But instead of selecting HDMI1 on the amp, I select Video1 to get this combination

This all works fine. But (and I really don't understand this at all) some options on the Sony TV are no longer available when the amp is set to Video1 instead of HDMI1.

- The options button on the TV (which would normally call up a significant list of options including Picture-in-Picture (or PAP as the Sony calls it) will not work at all

- The Home button on the TV will also not work

Why should this be so? There is no change to the TV connections. The HDMI lead to the TV is no longer carrying audio but the TV would not have processed this anyway. Both the Options feature and the Home feature are immediately made available when I select a different input option on the AV amp

I don't understand this strange behaviour on the TV based on a different setting on the Amp. But perhaps you cleaver guys can explain it to me