Paymnt of service tax on revenue share

Our organisation has entered into a non-exclusive revenue share based agreement with one equipment manufacturing company to to supply, install and maintain free equipment at our customers' premises for providing services in the brand ma,e of our organisation.. A specified percentage of the amount collected from the customers for the services provided wd be paid to the private company under the agreement. Now the company is claiming Service Tax also along with the portion of revenue share. will anyone Please clarify whether ST is payable, who is responsible for payment to ST dept, at what percentage,whether we can avail cenvat credit on ST paid and to what extent. An early and a very specific reply wd be much appreciated.
Thanks.