How can I create a 1920x1080p25 preset in Premiere Pro CS4? I need to edit some source material that comes in 1920x1080p25, with a pixel aspect ratio of 1.

However, I'm missing the presets for this, and the closest I can find is HDV 1080p25, which would be 1440x1080 at a pixel aspect ratio of 1.3333. When I try to customize it, I obviously can't just change the PAR or the frame size.

How do I create a sequence that handles my 1920x1080 content?
I don't use CS4 but in CS5.5 you can do it this way: Open the Composition dialog, open the Settings tab, and choose Custom as preset (this should be the first entry). Now you can change all parameters. To save you preset, click the button Change preset at the lefthand bottom.