Dear Deep,
create new Excise code
follow this procedure :-
Go to Administration ------>setup------> Financial ----> Taxcode
here you create new Excise Tax code .
give Tax code (like BED@0%) -----select CENVAT in Tax type combination ---- in BED column select
Code------select NEW----in BED Attrubutes create new code for 0%--select account for the code ---
click on Valid period here you need to give date and rate (0%)--- then add this tax code.
There is no need to create new formula .... you just need to create new tax code for % Excise duty.
hope this can help you.
Thanks ,
Ganesh