well i am new to this but i think what most do is render it out to lagarith. and then encode to mpeg2 with cce or other high quality encoder. but i think you should have been editing with 6 channels of mono wav for the audio and then you render that to an ac3 5.1 track. at least that is what i have been led to believe.you start out by separating the 6 channels before the edit then edit the video and 6 wav files all at the same time. then render the video and audio to separate tracks and let your dvd author mux them. but as i said i am new too and have not gotten to the point of a finished edit yet so get other opinions.