minor's service tax on rent

I and my minor son hold a plot jointly. I , from my income , constructed a commercial building to give on rent. I want my son to receive half the rent. Each of us expect to receive Rs.6 lakhs each year as rent. What will be my  service tax liability? The income of child will be clubbed with mine for IT purpose. Will the income of child also clubbed with mine for Service tax liability as it crosses the threshold limit of Rs.10 lakhs on clubbing.