If you have copied the operational purchaser role to a z role then you can remove the entire iview that gives the separate tab to put in the confirmation.
This way the operational purchaser will put in confirmations for ONLY the shopping carts he/she has created. Highlight the shopping cart (in the POWL) and the CONFIRMATIONS button becomes active. That way you bypass the necessity to search for a PO / SC (like in the separate tab for confirmations).