[OS X TeX] paper format in preamble

[RA Friedrich Vosberg]

Morning.

I've in MacOS X defined a custom paper format. To print a file in this paper format I have to press shift+cmd+p and to choose this paper format in the pulldown menu.

I would like to settle this by a command in the preamble of the TEX document, so that the paper format is set automatically while TeXShop is typesetting the output PDF file. How can I achieve this?

Thanks in advance and kind regards, Friedrich