InventSum Updates during Purchase Order ?

Hi All,

I am trying to update new InventDimId with InventSum table and want to understand where in the code InventSum table is inserted for the first time during the purchase Order. I am trying to update in UpdateNow() method of PurChFormLetter_PurchOrder, but by that time the InventSum table is inserted with some values and with wrong InventDimID (this DimID is what i am not looking for )…

Please help me with this…

Thanks//