How to check if an FTP directory exists

Basically trapped the error that i receive when creating the directory like so.

private bool CreateFTPDirectory(string directory) {

    try
    {
        //create the directory
        FtpWebRequest requestDir = (FtpWebRequest)FtpWebRequest.Create(new Uri(directory));
        requestDir.Method = WebRequestMethods.Ftp.MakeDirectory;
        requestDir.Credentials = new NetworkCredential("username", "password");
        requestDir.UsePassive = true;
        requestDir.UseBinary = true;
        requestDir.KeepAlive = false;
        FtpWebResponse response = (FtpWebResponse)requestDir.GetResponse();
        Stream ftpStream = response.GetResponseStream();

        ftpStream.Close();
        response.Close();

        return true;
    }
    catch (WebException ex)
    {
        FtpWebResponse response = (FtpWebResponse)ex.Response;
        if (response.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
        {
            response.Close();
            return true;
        }
        else
        {
            response.Close();
            return false;
        }  
    }
}