test.php

<?php
$username = 'pfr3$tuser7';
$password = 'hGcv%^*4534c8*-r45';
$url = "https://staging.partsvoice.com/rest/partsfilllocate";
$xml_data ='<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
                <partLocate>
                    <automakerID>FO</automakerID>
                    <partNumber>2L5Z-7D100-BA</partNumber>
                    <postalCode>78701</postalCode>
                    <quantity>3</quantity>
                </partLocate>';

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_MUTE, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-Type: text/xml',
    'Authorization: Basic ' . base64_encode($username . ':' . $password),
    )
);
curl_setopt($ch, CURLOPT_POSTFIELDS, "$xml_data");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$output = curl_exec($ch);
curl_close($ch);
header('Content-type: text/xml');
echo $output;
?>