VA01: I dont want to read salesorganisation (VKORG) via Parameter VKO

Hi Experts,

maybe this could be also be postet in the ABAP forum but I think its better postetd here.

I want to prevent SAP from suggesting the last salesorganisation (VKORG) when I create an Salesorder via transaction VA01.

The users simply pick the wrong salesorg to often if its filled automatically so I want to have it initial and the user has to choose one every time.

I found the spot in the coding where the parameter is set:

SAPMV45A
MV45AF0T_TRANSAKTION_INIT

  IF CALL_FUNCTION = SPACE.                          
    IF T180-TRTYP = CHARH.                           
      IF VBAK-AUART IS INITIAL.                      
        PERFORM VBAK-AUART_GET_PARAMETER(SAPFV45K).  
      ENDIF.                                         
      IF T180-TRVOG NE CHARB AND                     
         CALL_DIALOG IS INITIAL.                     
        IF VBAK-VKORG IS INITIAL.                   
          GET PARAMETER ID 'VKO' FIELD VBAK-VKORG.     "<- Here it will be picked from the parameter!
        ENDIF.                                       
        IF VBAK-VTWEG IS INITIAL.                    
          GET PARAMETER ID 'VTW' FIELD VBAK-VTWEG.   
        ENDIF.                                       
...

How can I prevent it? Is there a customizing mechanism or an user exit? I browsed arround but found nothing helpfull.

Best Regards

Manfred