To register a manual General Ledger posting (ATR) in period 13 & 14 when the period is closed in the coming year you must create a General Ledger posting (ATR) in the period that is open when you create the posting.

After it is registered, choose the option: 'Change Period' from the context menu.

You will be able to choose the period 13 and press enter. 

This is how you can move a General Ledger posting (ATR) to a period that is in status 6. 

Nb! remember to initiate import of the Inventory Balance (IB) for the next year when finished.