ELM Duplicate Check on BP fields

Hi all,

I am Using the Duplicate_check method of  BADI CRM_MKTLIST_BADI to prevent the duplicate data in the system. I am using the standard function module

CRM_MKTLIST_DUP_CHECK_INT in Duplicate_check method. But when i upload the same file with ELM more than one time the function module parameter lv_duplicates_found does not return any value.And the data save successfully.

CALL FUNCTION'CRM_MKTLIST_DUP_CHECK_INT'
       EXPORTING
         it_staging_adr      = it_mktlist_adr
         it_staging_per      = it_mktlist_per
         it_staging_org      = it_mktlist_org
       IMPORTING
         et_staging_dup      = et_duplicates
         ev_duplicates_found = lv_duplicates_found
         ev_error            = ev_error
         et_message          = et_message.
   ENDIF.

   IF lv_duplicates_found ISNOTINITIAL.
     ev_error = 'X'.
   ENDIF.

Here I want to know that is there is any other setting for activate duplicate check .

Am using the CRM 7.0 Ehp1 ver for this.

Thanks & Regards

Harish Kumar