why GL effective date is always end on the period

hi all

i have setup a new R12 oracle EBS setup,

with AP, AR, CM and FA,

they are doing weekly financial report.

but when we create accounting from sub-ledger  in 07- 12- 2013,  journal importing program always create journal with the month end date,

in above scenario its take  31, 12, 2013  as GL effective date. 

please tell me how to change GL effective date as Journal import running date. 

thank

nalinda