Remapping Keys using Ukelele?

I have a mbp and my "delete" key stopped working so I wanted to remap it to the F12 key in my keyboard. I downloaded Ukelele and for some reason it doesn't work, it won't swap the keys at all. I tried remapping it to a random letter key and it works fine. It just won't remap to a function key for some reason. Is there another software that will do the job? Any one have ideas?