echo return value from store procedure

Hi, I'm using SQLSRV driver for my php to communicate with SQL DBMS, and I found some problem that I cannot resolve (I'm pretty new in this)

my SP looks like this:

USE [Warehouse]
GO
/****** Object:  StoredProcedure [dbo].[AGCT_InsertOrder]    Script Date: 30.10.2012. 14:10:39 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[AGCT_InsertOrder](
    @User AS [int] ,
    @forwarder AS [nchar](4),
    @liner AS [nvarchar](100),
    @booking AS [nvarchar](30),
    @category AS [nvarchar](10),
    @customs_id AS [nvarchar](50),
    @customs_date AS [smalldatetime],
    @type_of_job AS [nchar](10),
    @need_weighing AS [bit],
    @need_sampling AS [bit],
    @username AS [nvarchar](20),
    @good_card AS [nchar](8) = NULL
)
AS
DECLARE @ret as varChar(6)
DECLARE @order as nchar(6)

SELECT @order = dbo.AGCT_GetOrderNumber()

IF @order = '??????'
    RETURN ''
if @good_card IS NULL
    SELECT @good_card = dbo.AGCT_GetCardNumber()
IF @good_card is null
    return ''

BEGIN TRANSACTION
BEGIN TRY

    UPDATE dbo.GoodsCard set  category = @category,goods_owner = @liner,forwarder = @forwarder ,[status] = 1
    where card_id = @good_card

    INSERT dbo.Orders SELECT
    @order,
    @User ,
    @forwarder,
    @liner,
    @booking,
    @category,
    @customs_id,
    @customs_date,
    @type_of_job,
    @need_weighing,
    @need_sampling,
    1,
    GETDATE(),
    @username,
    GETDATE(),
    null,
    null,
    @good_card    
    
    SET @ret = @order
END TRY
BEGIN CATCH
select @@ERROR
    SET @ret = ''
END CATCH
IF @ret <> ''
begin
    COMMIT TRANSACTION
    return @ret
end
ELSE
    ROLLBACK TRANSACTION

the goal is to get "return @ret" using php.

I found some interesting topics that are similar but it doesn't work for me:

This is my php code that I used to try to get ret value from SP.

<?php

session_start();
include('dbconn.php');
//if ($_SESSION['user']['password']) {

    if (isset($_POST['needweigh']) && isset($_POST['needsampl'])) {
        $needweight = 1;
        $needsampl = 1;
    } else if (isset($_POST['needweigh'])) {
        $needweight = 1;
        $needsampl = 0;
    } else if (isset($_POST['needsampl'])) {
        $needsampl = 1;
        $needweight = 0;
    } else {
        $needweight = 0;
        $needsampl = 0;
    }

    $dat = strtotime(str_replace('/', '-', $_POST['customsdate']));
    $date = date('Y-m-d H:i:s', $dat);

    if ($_POST['select_card'] == "") {
        $val = array(null);
    } else {
        $val = array($_POST['select_card'],SQLSRV_PARAM_IN);
    }

   // var_dump($id, $fwd, $lin, $book, $categ, $custmi, $custmd, $typ, $needw, $needs, $usrn, $val);

    $sq = "{call AGCT_InsertOrder( ?,?,?,?,?,?,?,?,?,?,?,?,? )}";
    $ret = "";
$params = array(
                 array($_SESSION['usrid'],SQLSRV_PARAM_IN),
                 array($_SESSION['fwdr'],SQLSRV_PARAM_IN),
                 array($_POST['liner'],SQLSRV_PARAM_IN),
                 array($_POST['booking'],SQLSRV_PARAM_IN),
                 array($_POST['category'],SQLSRV_PARAM_IN),
                 array($_POST['customsid'],SQLSRV_PARAM_IN),
                 array($date,SQLSRV_PARAM_IN),
                 array($_POST['type_of_job'],SQLSRV_PARAM_IN),
                 array($needweight,SQLSRV_PARAM_IN),
                 array($needsampl,SQLSRV_PARAM_IN),
                 array($_SESSION['user'],SQLSRV_PARAM_IN),    
                 array($val,SQLSRV_PARAM_IN),
                 array($ret,SQLSRV_PARAM_OUT,SQLSRV_PHPTYPE_STRING)
               );
    $query = sqlsrv_query($conn, $sq, $params);
    //var_dump($query);
    echo $ret;
//    if ($query === false) {
//        print_r(sqlsrv_errors());
//    }
//    header('Location:../insertSpecs.php');
//} else {
//    header('Location:../index.php');
//}
?>

what did I do wrong, how can I get return value from my SP...