Default Customer code in Sales order

Hi Experts ,

     Is there any option in SAP B1 to set a 'Cash' Customer as default when the sales order is loaded , After adding a document and in New Document Menu click. If there is no option in SAP B1, how can I do it using SDK. I already wrote code in '1282' menu click, and sales order Form Load. But i cant able to set the Default customer after adding a Sales order and the document refreshed to a new document.

I tried to do the same in FORM_DATA_ADD , BeforeAction=False and ActionSucess=True, but it cause some problem if document total is ZERO, when system message is pop up..

Is there any solution for this.

Thanks .