Availing Cenvat credit on abatement

Dear Sir,

  We're claiming abatement @ 35% on pharma products for the finished goods and paying the balance as excise duty .

  My question

-  Is it possible to avail cenvat credit on purchase and other input services fully?

- Will it make any difference while availing the CENVAT credit from ISD invoices? 

- Whether it Is affected by the amendment of scope of exempted services made in finance act 2011?

  expecting your reply at the earliest.