Availing of Cenvat Credit on Input Service received beofre t

I Would lIke to have your clarification on the below issue.

We are in teh process of registering our firm with the Service tax department for rendering service under category " Bussiness Support Services ".

May be i would have my registration done by 20.03.2009.

Our First Invocie will be raised on 25.03.2009 towards the service being provided by us.

My Point is that can we avail the cenvat credit of the service tax paid on some of the Input services.......Input services Invocie dated before the date of registration......consider the date of the invoice of the input service will be around 15.02.2009. ( Before the date of registration .

Kindly clarify.

Regards
Karthik