Creating batches with back date

Hi,

How can i create batches with back date and allow the sales order reservations to be done in that batch.

e.g:- current batches

                       Batch date

BATCH 1       1/2/2013

BATCH 2        1/5/2013

Need to create a new batch as BATCH 3 with the batch date  12/31/2012

Though I create the BATCH 3 with an earlier date. When sales order reservations are done, system still reserves items from BATCH 1 and BATCH 2.