Problem about BAPI BAPI_SALESORDER_CREATEFROMDAT2

Dear,

I have faced a problem that my customized fields can not be update when to create a SO using BAPI_SALESORDER_CREATEFROMDAT2.

During the tracing to this BAPI, I found the customized fields was filled and was passed into the function, but there is no customized fields found in the targeted internal table EX_VBAPKOM that is created basing on the structure VBAPKOM.

Any one can tell me how I should do ?

Can I append a structure holding the customized fields to VBAPKOM directly?

Thanks a lot!