iMac to TV (HDMI) : Ghost display when TV is off

Hi,

I'm using my Sony TV (40BX420) as my secondary display for my iMac 27", connected via

MiniDisplay Adapter+HDMI Cable. When connected everything works fine, the

audio & picture appears normally. I use this setup to watch movies on my bigger screen.

I always keep the hdmi cables physically connected between the TV & iMac (which is always on).

The problem is when I switch the input on the TV from HMDI to Antenna (to see the TV channels), the

hdmi appears active to my iMac, and the audio & windows which was getting displayed on the TV, does

not reappear on my iMac.

The only solution to my problem is to physically disconnected the hdmi cable when I do

not want to watch the computer content on the TV.

I'd an older Toshiba TV, when I connect the same hdmi cable to this tv. As soon as I change the input

on the TV to HDMI, the iMac responds, with activating dual monitor, when the change the input, or switch

the TV off (standby) the imac goes back to single display mode.

I call sony, their tech support is horrible, they told me it a feature of their TV, it keep the HDMI active in standby mode.

I tested this buy shutting down the power on the TV, but the iMac was still behaving as if connected and I've a ghost display

on the TV.

Please let me how can I solve this issue. They may quite a few of you who is connecting their iMac to TV

Sajid