tax configuration in India

Dear Friends

when setting up Item tax group and tax groups. to settle the following case;

SALES AGAINST C FORM.

YOU ISSUED THE FOLLOWING TAX:

EXCISE DUTY — 12%

SECOND EXCISE 2% ON THE ABOVE TAX RESULT.

SECOND EDUCATION CESS 1% ON THE ABOVE TAX RESULT.

CST 2% ----------- ON THE GROSS AMOUNT INCLUDED THE ABOVE TAXES.

to here is correct, but if we have to add the TAX CODE = ADDITIONAL TAX — 1% on the above, meaning

(total invoice value + excise duty + second excise + second ed. cess + CST)*1%

How to set up this. because if you calculate including other taxes for the last two tax codes, system go wrong.

please advise.

thanks

angel