protected Hc5FormScheme convertFormScheme(final Hc4FormScheme hc4Form) {
        final Map<String, String> params = new HashMap<>();
        final String[] keys = { "encoding", "token_url", "token_pattern", "token_name", "token_method", "token_parameters", "login_method",
                "login_url", "login_parameters" };
        for (final String key : keys) {
            final String value = hc4Form.getParameter(key);
            if (value != null) {