Im trying to add my own gateway using other gateways as reference, but im having problem with onClick. (Uncaught ReferenceError: $ is not defined at HTMLAnchorElement.onclick)
Maybe someone has idea why so...

<?php
class PayeezyPaymentOSP { 
    public function __construct() { }

function get_client_ip_env() {
    $ipaddress = '';
    if (getenv('HTTP_CLIENT_IP'))
        $ipaddress = getenv('HTTP_CLIENT_IP');
    else if(getenv('HTTP_X_FORWARDED_FOR'))
        $ipaddress = getenv('HTTP_X_FORWARDED_FOR');
    else if(getenv('HTTP_X_FORWARDED'))
        $ipaddress = getenv('HTTP_X_FORWARDED');
    else if(getenv('HTTP_FORWARDED_FOR'))
        $ipaddress = getenv('HTTP_FORWARDED_FOR');
    else if(getenv('HTTP_FORWARDED'))
        $ipaddress = getenv('HTTP_FORWARDED');
    else if(getenv('REMOTE_ADDR'))
        $ipaddress = getenv('REMOTE_ADDR');
    else
        $ipaddress = 'UNKNOWN';
 
    return $ipaddress;
}

      public static function button($amount = '0.00', $description = '', $itemnumber = '', $extra_array = null) {
      $extra = osp_prepare_custom($extra_array) . '|';
      $extra .= 'concept,'.$description.'|';
      $extra .= 'product,'.$itemnumber.'|';
      $r = rand(0,1000);
      $extra .= '|random,'.$r;

      PayeezyPaymentOSP::payeezyButton($amount, $description, $itemnumber, $extra_array);
    }
   
public static function payeezyButton($amount = '0.00', $description = '', $itemnumber = '101', $extra_array = null) {
      $extra = osp_prepare_custom($extra_array) . '|';
      $extra .= 'concept,'.$description.'|';
      $extra .= 'product,'.$itemnumber.'|';
      $r = rand(0,1000);
      $extra .= '|random,'.$r;
  $link = 'https://www.somesite.com/a/index.php?action=form_sms';
  $ip = get_client_ip_env;
    ?>

<li class="btn-payeezy">
<form class="nocsrf" action="<?php echo $link; ?>" target="_self" name="payment_form" id="payeezy_<?php echo $r; ?>">
<input type="hidden" name="post_amount" value="<?php echo $amount; ?>" />
<input type="hidden" name="post_currency" value="978" />
<input type="hidden" name="post_ip" value="<?php echo $ip; ?>" />
<input type="hidden" name="post_description" value="<?php echo $description;?>" />
<input type="hidden" name="post_language" value="lv" />
<input type="hidden" name="extra" value="<?php echo $extra; ?>">
</form>
<a id="payeezy-button-confirm" class="button btn-payeezy osp-has-tooltip" href="#" title="<?php echo osc_esc_html(__('You will be redirected to FirstData', 'osclass_pay')); ?>" onclick="$('#payeezy_<?php echo $r; ?>').submit();">Pay with card</a>
</li>
 <?php
}
}
?>


onclick="$('#payeezy_<?php echo $r; ?>').submit();"

You should call function that submit form rather that calling jQuery that probably does not work with onclick.

Did find out, that it is easyer to edit out some gatweay i will not use. (Skrill)
Now only need to think trough how to record all of it in OSP database

Managed to record all info in its test database, if i may ask one last thing (hopefuly), with payment has closes payment procesing to record all this in database logs?

I figured out how to do returnOK, returnFail link, but have problems figuring out how to record this transaction id in db before i move to payment procesors website.

  $amount       = $_POST['post_amount'];
  $currency     = $_POST['post_currency'];
  $ip           = $_POST['post_ip'];
  $description  = urlencode(htmlspecialchars($_POST['post_description'], ENT_QUOTES));
  $language     = $_POST['post_language'];
  $extra     = $_POST['extra'];



  $merchant = new Merchant($ecomm_server_url, $cert_url, $cert_pass, 1);

  $resp = $merchant -> startSMSTrans($amount, $currency, $ip, $description, $language);

        if (substr($resp,0,14)=="TRANSACTION_ID") {
                $trans_id = substr($resp,16,28);
                $url = $ecomm_client_url."?trans_id=". urlencode($trans_id);
               
                $sql = mysql_query("INSERT INTO $db_table_transaction VALUES ('', '$trans_id', '$amount', '$currency', '$ip', '$description', '$language', '---', '???', '???', '???', '???', now(), '$resp', '', '')", '$extra');
                       
                header("Location: $url");
                        if (!$sql) {
                            die('*** Invalid query: ' . mysql_error());
                        }

        }else{
                echo $resp;
                $resp = htmlentities($resp, ENT_QUOTES);
                $sql = mysql_query("INSERT INTO $db_table_error VALUES ('', now(), 'startsmstrans', '$resp')
                        ");

                        if (!$sql) {
                            die('*** Invalid query2: ' . mysql_error());
                        }
        }
mysql_close($link);

@SilenceXX
Osclass Pay never store transaction before it is really processed. Every gateway generate payment & process order once data are sent from processor back to web.

Im dumb then How does OSP tie transaction id to with cart is paid?

If im geting corectly, as soon i submit data/start redirecting to payment gateway, it gives me transaction id.
When payment is finished, it is identified with same transaction id. 
RESULT: OK RESULT_CODE: 000 3DSECURE: NOTPARTICIPATED RRN: 820009354952 APPROVAL_CODE: 714523 CARD_NUMBER: ****************and in $_POST trans_id   FBUPlQTvpqnvet3GtGRhQJNbQ4Q=

@SilenceXX
It sends all data required to generate order to processor and these data are then returned also with status of payment.

I guess will do then in dumb way, using its own database table as midway where to keep all transactionid and extra.

@SilenceXX
You may create help tables where transaction in "preparation" status will be held