No problemo...you can get them from fleabay Australia for as little as $3.96 free post...
here.
There are other Aust suppliers on line that sell stainless steel screws...sorry I've lost them for now! I don't know why they are around 1/2" long they can be shorter!
edit:
Ahhh
here the store is...the one I was thinking of. Same price $3.96 free .post