Service Tax

Hello,

Please go through the problem below:

Company "A" has a contract with Company "B" about providing man power to Co. "B".  Company "A" has hired qualified executive on their (Co.A's) payroll and provided services to B. However B is agreed to pay employee cost and 20% extra charge on employees cost to A. 

Now, will A load the service tax on 20% charge or on total bill including employees cost????

Limit is 10L that I know.

Please advice.