Hi,

for BAPI you need to Pass in the export parameter
1) Sales order Header data- this is a structure(like Doc 
type,Sales Organisation,Dist. Channel,Division,Purchase 
Order,Date.(mandatory)
  i) and you have pass the check box field 'X' for all     
these  above fields.
these below tables should be passed as internal tables to 
the tables parameter of the BAPI as
SOITEM , and check box for this field SOITEM_CHECK, 
SOPARTNER data, SCHD line data and check box field 
SCHD_CHECK text data SOTEXTDATA.