What about the hand nails? The only thing you have to do with bottom wall plates of non-bearing walls is to make sure they don't slide around. For a 12' wall you only really needto secure the ends, and 2 or 3 other spots because there will be no huge, critical lateral loads exerted. If hand nailing masonry nails is too tough you can pre-drill the holes using a masonry drill bit that is just a tad smaller than the nail shank. Heck, doing it this way you don't even really need masonry nails. With a non-hammer drill don't use too fast a speed or you will smoke the bit. Epoxy and construction adhesive also works wonders. Remember, the nails only need to go into the concrete by an inch to stop the plate from sliding so don't use nails longer than 2.5".