Gift Voucher Expiry option?

Hi -

Are there any extensions for or can someone assist me in modifying my OC 2.0.3.1 installation to add a gift voucher expiry function. I wish to be able to set a 12 month expiry from the date of issue on gift cards. After this date, the gift cards no longer work and become disabled.

This can apply to all gift cards or just a selection of gift cards where I can specify an end date upon creation.