Bed cover help please.

I searched, and couldn't find nothing to help so here is my situation. My truck came with a bed cover that has a lock, but no key. Anyone know how I could replace the lock or get a key for the lock some how? This is a link to a site that has a very similar cover, I don't have any pics mine at the moment, so i guess this will have to do. Thanks in advance. (Why do I need a lock? College is coming fast, and well it is more than likely going to turn into a storage space for me and any buddies that might need it, so the working lock is essential.)

http://www.autotrucktoys.com/ram/images/M82211524.jpg
http://www.autotrucktoys.com/ram/images/M82207089.jpg