Hi Gary -
YES - it can be done... but -NO - don't expect the powerpoint to look as crisp as it did before, or the transitions to be as smooth.
To do what you want, the powerpoint has to be converted into video format. This can be done simply with conversion software. You can download a free one here -
http://www.effectmatrix.com/PowerPoint-Video-Converter/Free-PowerPoint-Video-Converter.htm
1. The first step is to ensure the presentation has all its timings in place. If it was operated by mouse clicks during the lecture, you'll need to set each slide to required transition times.
2. Open EM Converter - select the presentation to convert it - select the video format, AVI, mpeg etc. & convert. All narration, music and transitions will be converted. You'll now have a video version.
3. Open PowerDirector - where you probably already have the edited footage of the lecture.
4. Import the converted powerpoint - place it on the timeline after the lecture.
5. When you get up to menus & burning to DVD, just make the converted presentation a new chapter.
That's the only way I know to go about it, because PD7 won't be able to import the PP presentation unless it's in the right format.
Hope this helps.
Cheers -
Tony
Tread gently and you'll hear the daisies grow...