Purchased 21.5 " iMac 2 mo back. It has Lion. Trying to hook up using adapter from Thunderbolt to cable and into HMDI in 42" 1080p Plasma Panasonic TV. Video normal. Audio comes out of iMac speakers but no surround sound (Sony setup) through TV. Called care line and went to Apple Store 2Xs. They could not help. Who can help me or send me in the proper direction. I read 20 pages or so here but could not locate an answer. I am a beginner. Thanks for any help!