How do I hide my posts and info from certain friends?

I am trying to hide my wallposts from two recently added friends but when I go to the place, their names don't show up as options. I go to Account>Privacy Settings>Customize Settings>Posts By Me>Friends Only>Customize>Hide These From>These People.. everyone else shows up but the two people that I added do not show up. Did I do something wrong? How do I fix this.