Look at the surround panner. Make sure your project is set up for 5.1 surround in the properties, and each audio track should have a "surround panner". You can double click on this and adjust the panning "marker" to move the sound toward any location. This can also be key-framed, so you can start the audio track panned back, and keyframe it to move forward (or however you want).

Thanks a lot. That's exactlyl what I need.