Fetch VBAK / Sales header details in smartform driver program

Hi

Does anyone know how to fetch sales order header details i.e. vbak during runtime in smartform driver program in VA01 ?

Currently driver program is fetching vbdka details through FM 'RV_DOCUMENT_PRINT_VIEW'.

And it should be fetched during run time i.e. when this driver program is called through VA01 and the sales order number has not yet been committed to Database.

Thanks for your help in advance...appreciate any help !!