It is true a regular DVI to hdmi cannot pass through audio but ATI's adapter is different. What it does is it tell the video card to handle the DVI as an HDMI, that's how it passes audio.
I've used it on my htpc and it works; no bitream though you need a 5000 series for that. It only works with ATI video cards. I think the new nvidia GTX460 can do the same.
HIS ati adapter can pass audio:
"Enjoy the ultra-high definition video and audio HDMI delivers"
http://www.newegg.com/Product/Product.aspx?Item=N82E16814999010It does not really matter now as most AMD/ATI cards today have an hdmi port.
na check ko yung acer laptop ni txtus. video card is a nvidia graphics 7000 i do not think it will pass audio.
maybe a usb DAC can help?