How to modify what comes out of Description fieldon the LedgerTransStatement Report

Hi All I have an issue i am trying to solve, All transactions that come through the Purchase Order are returning “Vendor invoice” on the description column of the LedgerTransStatement report. I want it to output either the Product name[PurchLine.ItemName()] or the Procurement category [Ref_EcoResCategory_ProcurementCategory.Name] on the Description column.How do i achieve this.

Additional Info…

Navigation>>General Ledger>>Main Accounts>>(select main Account from PO distribute amounts)>>Account.

Additional info…First you have to know the main account which the PO was distributed to i.e Accounts Payable>>All P.Os>>open any invoiced account>>PO Lines>>Financials>>distribute amounts(and ledger account is the Main account)