I just bring the 16:9 footage into a standard 4:3 project and scale it to fit as letterboxed. Add the 4:3 footage and the 16:9 footage together and it works fine as a 4:3 project.
In order to set up the ability to pan and scan the 16:9, I use a letterbox title over the video to restrict it to the original shape. Although, I often find a lot of HDV footage that works as 4:3 when zoomed in a bit anyway.
Steven
Adobe Premiere Pro 1.5.1 / After Effects 6.5 Pro https://www.stevengotz.com
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