DD 5.1 in nested project?

[Piotr Wozniacki]

OK, so I have rendered a 1h:30mins HDV project using the 1440/24p template and burned it in my new Vaio's burner - first BD in my life! All wen well, and is playing fine...Except for this:

I'd like to stretch my projects, consisting of 1080/25PsF clips, so that - after changing the project settings from 25 to 24fps - the duration is unchanged (Bob has explained the method to do just that). However, I cannot seem to able to stretch the project as a whole (3 video and 2 audio tracks), even after having grouped everything! So I thought I'd try to nest the whole project into a new one, already 24fps - now the stretching works, but I'm loosing the 5.1 Dolby audio! I don't know why, but nesting the project only brings one audio track in (the original stereo, recorded with the camera mic); my Cinescore generated music which in original project I redirected into surround channels don't come through at all!

Why is that? In the original project, all is fine, i.e. I can pan the original audio to the front, and the generated music to the back speakers...