Income Tax Calculation..India payroll

Hi Experts,

I need a help regarding Tax Calculation .Here my client is calculating tax outside of sap.Now they wish to have with SAP.The client is saying that at some point of time in the lastyear they have deactivted Tax calculations by sap. At present they are calculting tax by an excel sheet.Through an wagetype they will put that amount in deductions.

How can i activate the system to calculate sap.What could be the first step.

Please advice me to solve the issue.

Thanking you.

Regards,

Sai.