How to close the open sales orders through bdc?

hi friends,

      i want to close the open sales orders through VA02 transaction using BDC, when iam using BDC  material 1 having the item number 1,

      material 2 having item number2 this situvation it is working good, but some times Same sales document material1 having item number2, this situvation open sales order not closed .

  if any body know please tell me the solution.