Customer fields of Purchase Order set through EXIT_SAPMM06E_013 are not updated in DB

[mathieu_l1]

I'm trying to update a customer field in table EKPO when transaction ME22N is used. I've extended EKPO by adding a field ZZTEST to CI_EKPODB.

I've added the following code in FM EXIT_SAPMM06E_013 to set the values of the custom field in internal table XEKPO.

  LOOP AT xekpo[] ASSIGNING FIELD-SYMBOL(<fs_ekpo>).

    <fs_ekpo>-zztest  = 'TEST OK'.

  ENDLOOP.

The code is called and the internal table is correctly updated. However, the value of ZZTEST is not updated in the database (table EKPO). The other standard values changed in ME22N are correctly updated in the DB though.

I must have missed something. Please help.