Posting Order

Hiiiii Iam new to Axapata, In Ax-2009 ,I created 2 fields in InventTable and on Purchase Order also Placed same Fields When I Clicking Posting->Purchase Order Data is not updating on Newly created fields and on history Table also not effecting.Can u please help me what are the classes that are Hitting and what is the Procedure to do this Requirement.

thank u in Advance…