Adding a OH Misc Charge during EDI Import

Does anyone know if it’s possible to add a misc order header charge to an EDI order during the import process? Currently have an ImportEDIPostProcessDemand Post Processing BPM that checks a few things before setting the Ready To Fullfull box to true. Trying to add logic before this by calling boSalesOrder.GetNewOHOrderMsc(ref dsSalesOrder, OrderNum, 0); but it seems to be bypassing the entire BPM now. Not sure what we are missing.

foreach(var OrderHed_iterator in (from OrderHed_Row in Db.OrderHed
                                  where OrderHed_Row.Company == DemandHead.Company &&
                                        OrderHed_Row.DemandHeadSeq == DemandHead.DemandHeadSeq &&
                                        OrderHed_Row.OrderNum == DemandHead.OrderNum
                                  select OrderHed_Row))
  OrderHed = OrderHed_iterator;
  if(OrderHed != null)
    //OrderHed.ReadyToFulfill = true;