Can we deduct TDS on service tax? can you give some references?

I am a professional consultant, on my total fee amount (gross amount) I add service tax @ 12.36% to arrive at the bill amount (net amount) payable by the clients. While making the payments, clients were deducting TDS on whole bill amount(Net amount) which includes service tax too, when I argued with them that service tax is not my income and it is paid to the government in total, therefore TDS not to be deducted on service tax amount, some clients agreed and others did not. Can you give lie conclusive reference / Guidelines in the matter so that I may convince my clients for not deducting TDS on service Tax