How To call standard interface program 'Project Transaction Import'

  Hi All,

Can anyone please suggest me how to run the standard Project Transaction import program via PL/SQL API.

I am using below query but it i snot working 

ln_request_id :=

         fnd_request.submit_request (

                                      application => 'PA',

                                      program => 'PAXTRTRX',

                                      description => '  ',

                                      sub_request => FALSE,

                                      start_time => TO_CHAR ( SYSDATE, 'DD-MON-YY HH:MI:SS' ),

                                      argument1 => 'BX WebAdi',

                                      argument2 => 'BX_Test_G12',

                                       );

   From the screen ( SRS window Form ) , I noticed that Operating Units  gets defaulted , but there is no way I can pass the org id  via sql in above query . 

Can anyone please suggest what should be the ideal way to perform this action . ?