PHP and MS SQL (with sqlsrv driver) return value

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I'm working with a MS SQL database that was done by another developer. Im developing a website that interacts with that database. I need to use a stored procedure called LoginR that takes 3 input parameters (LoginName and Passwords) and returns the NickName in the third value. But also, has a "return" command that returns the ID of the user. Here is the procedure as I see on Microsoft SQL Server Managment Studio:

USE [myDataBase]
GO

DECLARE @return_value int,
        @NickName nvarchar(100)

EXEC    @return_value = [dbo].[msp_LoginR]
        @LoginName = N'MyUser',
        @Password = N'MyPass',
        @NickName = @NickName OUTPUT

SELECT  @NickName as N'@NickName'

SELECT  'Return Value' = @return_value

GO

I can run perfectly the stored procedure in PHP in this way:

        $procedure = "{call msp_LoginR( ?, ?, ?)}";
        $LoginName = $_POST['user'];
        $Password = $_POST['password'];
        $NickName = '000000000000000000000000000000000000';
        $params = array( 
            array($LoginName, SQLSRV_PARAM_IN),
            array($Password, SQLSRV_PARAM_IN),
            array($NickName, SQLSRV_PARAM_OUT)
        );

    $res = sqlsrv_query( $conMS, $procedure, $params);

And after doing that I got my variable $NickName with the correct value. But I can't get that 'Return Value' = @return_value that the Stored procedures send me and it's the user's ID. What I need to do?