File creation/modification time in remote server

Question

I've got this code:

$cntx = stream_context_create(
    array(
        'smb' => array(
            'username' => 'me',
            'password' => 'mypass'
        )
    )
);

$dir = 'smb://192.168.100.222/MY_FOLDER$';
if ($lst = opendir($dir, $cntx)) {
    while (($file = readdir($lst)) !== false) {
        if (substr($file, -3) == 'PDF') {
            ...

I need to get each $file creation time to compare with files in my machine. There's other machine I need to access, how can I have this file creation info in original server?

filemtime and filectime does not work in this case... I have no alternative ways.