Gross tax procedure

Dear Experts,

One of my client want to follow Gross tax calculation procedure while purchasing and selling the materials, Please let me know where i need to do setting/customisation in order to calculate Gross tax instead of net tax procedure in MIRO for purchasing and In Billing for sales.

i have not selected fields "Tax base is net value" in OBY6 and "Calculate taxes on net amount" in traxn.. FB00, but still system is calculating tax on net value only.

Regards

babu