Hi Prashant,
I am able to implement the solution at least now on GTS 10.1. The only thing we all might be missing is the implementation of the second BADI in ECC given in the document. Its just that this BADI is called up at Sales Order or Delivery creation in ECC and it explodes the document related BOM and creates an entry in tables /SAPSLL/BOMHD and /SAPSLL/BOMIT in GTS with service LECLDT and a value in KMAT_IDENT which links the BOM with the customs document.
Now, how to implement that BADI is a different question because you need to write your own logic of BOM explosion in ECC.
regards,
Kul Vaibhav