Hi,
To downmix (render to a new track) you have to be on the sound card (or the output, for a multiple ouput sound card) that is chosen in the windows sound and audio device propeties as the "default playback" device. So even if you downmix on the master bus it won't work if it's not routed to the default device. This is a major problem for any one that has a profesionnal setup with a multiple output sound card (or more that one sound card, wich is my case). This is really strange... It should be able to render to a new track with any device selected.

In vegas 2 you can actually render from any bus or device selected, and it all stop to work from vegas 3.

M.Mike S respond to me . But I think I did not explain myself clearly and since I did, I had no response. He told me I should write to the engineers. How can I do that and have a response from them?

Well, I waiting for news on this. I really need to know if this is going to be fix. My compagny is waiting on this to know if we keep using vegas or not.

Thank you. Have a nice day.