Ser Tax paid on advanace recived

DEAR SIR 

A LARGE EPC CONTRACTOR RECEIVED ADVANCE FROM IT'S CONTRACTEE FOR ESTABLISHING A PLANT.

HE PAID THE SERVICE TAX ON WHOLE AMOUNT RECIEVED AS PER THE LAW.

NOW IN THE SUBSEQUENT PERIODS (MORE THEN 1 YEAR LONG) WHILE EXECUTING THE SAME PROJECT HE IS RECEIVING INPUT SERVICES/GOODS ON WHICH CENVAT CREDIT IS AVAILABLE. 

HOW WILL HE GET THE CREDIT OF CENVAT? SHOULD HE ADJUST IT WITH FUTURE RECEIPTS OR APPLY FOR THE REFUND CLAIMS? 

WHAT IF THE WHOLE AMOUNT IS RECEIVED IN ADVANCE?