Dear Vasant,
Just tell me how this arrangement is different from some security agency? For security agency, to perform their operations, you provide them facilities like furniture, shades for the security guards, locker to change their dress etc. Security personnel come, do their duties and go back. For providing these services, if you check their bill, you will find that the component of PF/ESI too.
Therefore, in your case owner of the drivers' agency, should include PF/ESI in the bill itself. To be on the safer side it is better to mention the PF/ESI component against each individual too. Secondly, ask the agency to provide xerox copy of monthly return also.
For Sebastian KS: - You have written that "It is better to have a service contract with the bus owner. Thus you dont need to employee a driver. what you want is that your employees are picked on the dates sspecified. Since you dont give salary to the driver, you dont need to pay PF/ESI. But the payment you are giving to the bus owner, you may have to give service tax."
In the above case, you need to pay ESI. If the labour component is not mentioned in the service contract then you have to assume 40% of the contract amount is labour charge and pay the ESI monthly. Onus for payment is on the principal employer in such case.
DVD