Cenvat input credit

Hi

our company sells product on which service tax and excise duty is not charged but on the sale invoice we charge shipping charges also on which we charge service tax. shippping charges recovery is almost 3% of total revenue

can somone pls help me on how to claim cenvat input tax credit. shipping cost/bill is separately identifablle which we recover. can we take 100% cenvat input credit on shipping/courier bills against servicw tax payable on shipping recovery amount.