Taxability of trasporter

hi, 

my client owns two trucks and he in the year 2011/2012 supplied building material to up rajkiya nirman nigam of composite value of Rs. 350000 (inclusive of material supplied's cost).

now since it was a composite contract and service portion is not determinable then is there a service tax liability on the transporter and if the answer is yes then how to calculate his service tax liability.

also does reverse charge mechanism will be applicable in this case after providing for abetment of 75%

please reply urgently

thanks