You can create your AE comp at D1/DV PAL Widescreen and use PAR button (or a 16×9 monitor) while working. Or you can create your comp at 1024 x 576 square pixels (no need for the PAR button) then drag that comp into D1/DV PAL Widescreen comp for the final render. You can also work at 720 x576 D1/DV PAL Widescreen in Photoshop (this is a feature included from Version 7) and use the PAR setting but I prefer to use 1024 x 576 square pixels when working in Photoshop.
John Dickinson
Motionworks
https://www.motionworks.com.au