How to calculate begining balance in SSRS.

Hello,

I am designing vendors ledger on ssrs. But I have a challenge, I  couldn't calculate the opening balance/balance brought forward for vendor.

For instance vendor transaction have been in existence since 2000.

and I want to run his ledger from 01-101-2013 to 31-12-2014 but I will like to see his balance as at 31-12-2012

Please how do I get this done.

Thank you

Akintayo Kemi