cer/key to pfx

cer2pfx.php

<?php

//package up pem encoded certificate and key into a pfx (PKCS #12) file with your handy-dandy already installed php.exe.

$outpfx = "./out.pfx";
$cert = openssl_x509_read(file_get_contents("./domain.cer"));
$privatekey = file_get_contents("./domain.key");
$passphase = "somepass";
openssl_pkcs12_export_to_file($cert, $outpfx, $privatekey, $passphrase);