<?php
$outfdf = fdf_create();
$volume = "test";
fdf_set_value($outfdf, "volume", $volume, 0);
fdf_set_file($outfdf, "http://localhost/webapps/volume.pdf");
Header("Content-type: application/vnd.fdf");
fdf_save($outfdf);
fdf_close($outfdf);
?>
This works for IE 5.5+
It will populate the fields and open the resulting pdf for you, without having to create an fdf file and adding the open script to the pdf...