Service tax on commission income

Hi

we are a pvt ltd company in india.  we operate as agent / representative for foreign product manufacturers to sell their products to customers in India.  The manufacturer receive the order from indian customer and the indian customer import the goods and make payment direct to foreign supplier. we only receive commission in india in foreign currency from foreign manufacturer. Does this attract Service Tax applicability ? If so, what is the exemption limits.  Pls advise.

Thank you.