SRM SUS open new window

Hello all, please can you help me its urgent

I have requirement in SUS i added a custom button on  sus ASN  now clicking that button i have to open another window i'm able to open a new window but current page goes blank

i handled DO_HANDLE_EVENT of class CL_SUS_C_ASN_DETAIL_EDIT code is below

CASE event.

   WHEN lc_zatt_btn.

     cl_wd_utilities=>construct_wd_url( EXPORTING application_name = 'ZWD_TEST'  IMPORTING out_absolute_url = l_wd_url ) .

     navigation->CALL_APPLICATION(  url = l_wd_url  ).

*

     navigation->use_auto_submit_form( '1' ).

ENDCASE.

Regards

Mohammed Sajid