You'll probably find that the TV will do this if you use a remote that has the correct button.
Unfortunately, the RM-ED044 does not produce the "Previous channel" SIRCS code.
My KDL-40EX723 TV works with the "Recall" button on a RMVLZ620 remote programmed with Sony codes. This is a programmable remote similar to a One-for-all type. Generally, most Sony TVs will implement the function, even if the supplied remote does not produce the code.
I made a suggestion to Sony that it would be a very nice feature to have a "Previous channel" key on the RM-ED044 remote.
This could be achieved in the TV software by giving us an option in the menus to remap the "Audio" key function on the remote (small button next to the "PROG" buttons) to either function as it does currently (I never use it) or to perform the function of returning to the previously selected channel.
This would be extremely easy for them to implement, but I know they won't do it. That would be far too helpful!
