So far I have not been able to drop the rendered SD show into the 1920x1080i timeline and get the pillerbox cropping that I need for export. It fills the frame and when I try to scale the picture down it is cropped top and bottom.
Specs are: M100 2.1.2 with Matrox MX02.
Of course I am willing to hear that this is just not the best way to do this.
So you have SD 4:3 clips? And they are interpreted as 4:3? You can check that either in the Bin List view under "Aspect Ratio", or by Right-clicking on your clip in the Bin and selecting "Change Media Attributes". If it is set to 4:3, you should be able to drop it into a 16:9 timeline (HD or SD), and it will show up as cropped, taking the center out of the image. If you then double click the clip in the timeline to load it into the Edit Suite, you can access the "Motion Editor" from the "ClipFX" part of the Edit Suite window (or select the clip in the timeline, and go to the Tools->Motion Editor Menu entry.
In the Motion Editor, you will see three icons that somehow look like keyholes in the lower tools row. Select the leftmost one; then you will see the green area which is taken out of your 4:3 image. If you want to use the full height of your 4:3 image, leaving black borders left and right, you can use the "Fill Height" button on the left hand side. If you switch to the middle "keyhole" button, you will see your resulting image. Press ok, apply the effect and you are good to go.
Btw., in the Motion Editor you could also do pan&scan moves, taking different parts of your 4:3 image to fill the 16:9 screen,…
Of course you can also do it via the "Conform" tool to conform a 4:3 clip or sequence to HD, using various settings and approaches.