Recently I found a new workaround for that.
- Install VoodooHDA (if it is already installed skip this step)
- If your volume control works turn it up to maximum , if it doesn't - leave it
- Install Soundflower (http://cycling74.com...ts/soundflower/)
- Go into System Preferences > Sound > Output and change your output to Soundflower (2ch)
- Launch soundflower , click on the menu bar icon and change the 2ch device to "Headphones / Speaker"
PS: Don't forget to add Soundflowerbed.app to your login items