Adjustment Period is not available on the Posting Period when creating a posting transaction

As per Help article "Adjustment Periods", You can only post journal entries to an adjustment period. Adjustment periods are not available in the Posting Period dropdown for non-JE transactions.  
 
If an accounting period is setup as below: 
1. Dec 2013 : Start Date: Dec 1, 2013 to End Date Dec 30, 2013 
2. Adjust 2013 : Start Date: Dec 31, 2013 to End Date Dec 31, 2013 
 
The Dec 31, 2013 can only be used for Journal Entries. 
 
If Dec 31, 2013 will be used for transactions other than journal entries, the Dec 2013 accounting period can be setup until Dec 31, 2013. To correct the accounting period: 
1. Setup>Accounting>Manage Accounting Period 
2. Edit Dec 2013 
3. End Date is Dec 31, 2013