There's an even easier way: Render the picture as you'd like it for the MAT pose. Go to Display: Paste as background. Swing the camera around so the actual figure isn't visible, just the background. Now save the pose under the name you'll use for your MAT file. Voila! A nice .rsr file with the correct name. Via Windows Explorer, go and delete the .pz2 file. Put in your MAT file under the same name as the deleted .pz2 file. Now your MAT file has a pretty .rsr file. I do it all the time. It makes life easier.