It looks like you have the recessed subfloor throughout the entire shower area. Are you trying to slope the rest of that area?
They do make a 1 foot wedi extension that could bring that area out
http://www.masterwholesale.com/wedi-fundo-ext2.html
But I think 60″ of shower base is enough area that very little water will extend past that. You could make sure you have your floor tile slightly sloped when installing. That is pretty easy to do if you plan to use a large tile.
