Here's an idea that should get it done for you, though it will cost some money (though not necessarily a lot). Use the Zone2 or Zone 3 audio outputs...
Based on posts across the board, seems like it's a problem that afflicts some sets but not others. (Seems to me I even remember one fellow exchanging...
If the source is connected to the receiver rather than to the TV, ARC is not involved. Regardless, the TV identifies itself to external sources as a...