Service tax on commission to full time employee on sales

For example A is a full-time employee of XYZ enterprises, XYZ pays commission to A for sales of goods of the firm over and above his fixed salary every year. will A be liable to pay service tax if his commission income ( as an incentive from the firm) is over 10 lacs in a year received from the employer. I have heard that service tax is not applicable in the employee-employer relationship and if an employee is a full-time employee.