yeah that should most likely a workable code by putting it on this table.
another approach can be adding code in at following location
\Classes\PurchPurchaseOrderDP\setPurchPurchaseOrderHeader
just before/above this line of code
purchPurchaseOrderHeader.insert();
you have to add a string type field, in your PurchPurchaseorderHeader , in this case and that would reflect the String/Amount in words on SSRS