Air travel agent - service tax

Dear Sir,
We are Air Travel Agents and books Air ticket (International) for few airlines. We get commission from airlines for the sale of ticket and that is the only income in this operation. 
We sell these tickets to other sub agents (B-to-B) as well as walk in customers (B-to-C).
We pay service tax on the commission we receive from the airlines @ 14%
Sir, can you please explain whether we have to charge services tax to the tickets sold to customers i.e. on B-to-C sales at the rate 1.4% on the basic fare (Since its a composition scheme and is optional). Various dealers have started this practice. But in my opinion its a composition scheme and optional and we are not under any obligation to charge at 1.4% to any sales ie either to B-to-B and B-to-C sales. 
Please guide.
Thank you in Advance .