Hi Ankur,
At the time of asset master creation under leasing tab you have to mention all leasing details i.e.lease start date,base value,no of lease payment,interest rate,lease payment,lease type etc. After save the asset, go to AS03 select the asset and click on leasing tab, here system will display opening posting icon, if you click on it, then system will post accounting entry.
Regards,
Mukthar