问如何使用运行在Apache2.4上的PHP5.6从SSL_CLIENT_*证书中获取SSL_CLIENT_*变量？

EN

<VirtualHost *:443>
    ServerName myserver.name #Omitted
    RequestHeader set SSL_CLIENT_SAN_OTHER_msUPN_0 "%{SSL_CLIENT_SAN_OTHER_msUPN_0}s"
    RequestHeader set SSL_CLIENT_SAN_Email_0 "%{SSL_CLIENT_SAN_Email_0}s"
    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html
    # Configuracoes de cache    
    Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
    Header set Note "Cache desabilitado no servidor/host"

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
    # Configuracao do SSL
    SSLEngine on
    # [...] Certificados AC e certificados da aplicacao: OMITTED
    SSLOptions +StdEnvVars +OptRenegotiate -StrictRequire +FakeBasicAuth -ExportCertData  
    # Solicita certificado SSL/TLS do cliente            
    SSLVerifyClient optional_no_ca 
    SSLVerifyDepth 3

    <FilesMatch "\.(cgi|shtml|phtml|php)$">
        SSLOptions +OptRenegotiate -ExportCertData -StrictRequire +FakeBasicAuth +StdEnvVars
    </FilesMatch>
    <Directory /usr/lib/cgi-bin>
        SSLOptions +StdEnvVars
    </Directory>
    BrowserMatch "MSIE [2-6]" \
                 nokeepalive ssl-unclean-shutdown \
                 downgrade-1.0 force-response-1.0
    BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown
</VirtualHost>

<?php //index.php

// Get client certificate data
$cn = $_SERVER['SSL_CLIENT_S_DN_CN'];
$email = $_SERVER['SSL_CLIENT_SAN_Email_0'];
$id = $_SERVER['SSL_CLIENT_SAN_OTHER_msUPN_0'];

$client_certificate_data = [
    'cn' => $cn,
    'email' => $email,
    'id' => $id
];

echo json_encode(
    $client_certificate_data,
    JSON_NUMERIC_CHECK
);