Thanks Raymond. Your advice help me solved this issue. These are the following things I did in IF_EX_ME_PROCESS_PO_CUST~PROCESS_HEADER.
- Insert address using ADDR_INSERT with address_handle = 'INDIVIDUAL_VENDOR_ADDRESS'
- Assign value 'INDIVIDUAL_VENDOR_ADDRESS' to variable (SAPLMEPO)ADDRESS_HANDLE
Anyway I didn't have to assign an address number to MEPOHEADER-ADRNR.