How to set page position in xpdf

How to set page position in xpdf?

Hi.

I wish to have in xpdf what I get in xdvi with the `topmargin' option, i.e.:

with the up and down arrows of the keyboard I adjust the vertical page position
as I want and then, every time I do `n' or `p' to move one page forward or
backward, I want that position not to change.

Is that possible, and how?

Thanks for any help
Rodolfo