title: how to add state wise tax charge without adding customer and product class
body: <p>my question is bit technical. i want to ask if i belong to state named NJ, and i want apply tax rule only on this state, means if user selects NJ on checkout as its billing state it should charge him 7% extra in checkout. i have made the tax rule as well but unable to implement on front end. i want this without influence of product and customer class. if i am wrong please give me proper direction with step by step guide. i am using magento 1.8.0. 
  please help........................
  what sort of custom code need to include or should be wrote by me??
  no more lucks please so give me guide..</p>