User exit for Saler order Idoc

We´re trying to create Sales Order through IDOC. I need to add several fixed values. I wrote a user exit in EXIT_SAPLVEDA_009 ( VEDA0001):

*----

segmentE1EDK17----

-

read table DEDIDD with key segnam = 'E1EDK17'.

if sy-subrc eq 0.

v_index = sy-tabix.

v_e1edk17 = DEDIDD-sdata.

* - Fixed values --

-

v_e1edk17-QUALF = '001'.

v_e1edk17-LKOND = 'CFT'.

*----

-

dedidd-sdata = v_e1edk17.

modify dedidd index v_index

transporting sdata.

endif.

I debugged the coding, the structure receives the values , but when I check the Sales order nothing appears .. Help !

Is there something to flags ??