Gift Cert as Attribute? Possible?

What i want to do is offer a gift cert with the purchase of a product. So i was wondering if there was a way to setup an attribute for the product which would add a 20 cert (which i already have setup per the instructions) to the order. No need to charge them, but i just need it to show up below the product so we know to issue one.

Currently i have it setup as a READ ONLY attribute with the text FREE 20 GIFT CERT WITH PURCHASE.

Is there any cleaner/better way to do this?
Thanks
Benjamin

No this one is not quite going to work ...

A Gift Certificate needs to have the products_model start with GIFT and be marked as Product is Virtual YES

As just an attribute of a Product ... these two conditions will not exist ...

As a READ ONLY ... you can tell them about it and then later, when processing their order, send them the Gift Certificate ...

However, there is no record of this READ ONLY attribute on their order for them or for you ... as it is READ ONLY and that means just a display ...