Retrieve subjectAltName from client certificate

[Nelson Teixeira <nelson777@xxxxxxxxx>]

Hello,

 I'm trying to read subjectAltName field from a client certificate with

$x509 = openssl_x509_parse($_SERVER['SSL_CLIENT_CERT']);
$subjectAltName = $x509['extensions']['subjectAltName'];

but the field contains " othername:, othername:, othername:," where the
real data should be. There's valid data there because I can see it in
firefox's certificate view. I already have SSLOptions +StdEnvVars
+ExportCertData configured in apache. I can read correctly serveral other
fields.

How can I receive correctly from apache and extract the real data ?

-Nelson