X64 not listed in platform, but only in active solution platform?

So I wanted to create a X64 bit version of my project.

So I created a new solution platform in the configuration manager.
X64 based on win32

So I select X64 for solution but under platform only Win32 is listed, if I try to create a new x64 under platform I get "This platform could not be create because a solution platform of the same name already exists"

 Any help? Am I missunderstanding how this is suppose to work?

 Thanks!