ST input credit

frnds,

For AMC charges paid for the period say 1.1.10 to 31.12.10, the amount pertaining to the period 1.4.10 to 31.12.10 booked as prepaid expenses during the Fy 09-10. The full amt of service tax paid for AMC can be availed as input or only amount pertaining to the three months can be availed?