How can I get a listing of files in a directory over SFTP in PHP 4.3?

I need to get an array of strings containing the list of files in a
specific remote directory over an SFTP connection.  I am using the
ssh2 PECL package (http://pecl.php.net/package/ssh2) deployed on Free
BSD 4.7.  I can successfully get a connection and even get a specific
file using fopen().

Tried unsuccessfully:
$connection = ssh2_connect($ftp_server, 22);
ssh2_auth_password($connection, $sftp_user_name, $sftp_user_pass);
$sftp = ssh2_sftp($connection);
$dir = dir("ssh2.sftp://$sftp/$ftpPath");

Ideally, I would prefer not to use an external process (proc_open) as
I am using a password for authentication.