Service tax at lower deduction & on softex

I am working with a 100% EOU for IT Software Services and we are also registered under STPI, I'd like to know following:

1. Is the export services (software developement charges) taxable under Service Tax Act?

2. Is there any way to restrict my vendors to levy Service Tax on the invoices (Similar to Section 197(1) of IT Act for lower deduction of TDS) e.g. Rent, Transport, consultancy etc.

3. Our Sister Company bills us for the Broad Band Charges & we pay them on monthly basis, do I need to deduct Tax on such O/w remittances?

Thank you in advance

GK