PPCO0007 User Exit for Changing Header Fields During Order (CO40)

.. Hi !!!!

  I need your help or suggestions,

  I need to change the standar order  before to save, i found the user exit PPCO0007,

  i assign the new value for the order, but when finish the fuction, EXIT_SAPLCOZV_001, the new values are

  lost, and finally the system set the standard order.

    Someona know how can change the order and the the batch.

     Thanks

Noemí Huerta