First of all we got to clean the original jack with some contact spray for electronics. Just spray a little inside of the jack and plug your headphones in and out several times.
Next step is to open your DMG up with a Tri Screwdriver which you can get at http://www.kitsch-bent.com for example.
Now locate the pins shown in the picture and solder like shown. I used normal ribbon cable which is working fine for all of the DMG mods. The white cable is used to turn off the speaker when plugging in headphones.
|this is how it should look like|
Once it looks like in the picture, test your audio with headphones -> make sure both audio channels work.
After that test if the speaker works and turns on and off when plugging headphones in.
You are done, congratulations!