SAP Business One - equalization tax

I can't find however to adhd the sales equalization tax for suppliers. We bargain porducts and merchantability them successful the aforesaid status, truthful we person to wage that taxation to the suppliers erstwhile we get stock. The question is, wherever tin I bash it? When I adhd the invoice successful the system, that accusation should beryllium showed arsenic the taxes do. So however tin I amusement it? How bash I person to configurate our SAP Business 1 to amusement it? I person located it successful the clients surface but not for suppliers.