The CENVAT credit in respect of input or capital goods purchased from a first stage dealer or second stage dealer shall be allowed only if :-
• he has maintained records indicating the fact that the input or capital goods was supplied from the stock on which duty was paid by the producer of such input or capital goods and
• only an amount of such duty on pro rata basis has been indicated in the invoice issued by him.
Hence FSD/SSD has to compulsorily mention purchase details in his sales bill
Also he has to maintain specific records of purchase and sales (Prescribed format is RG 23D)