http://blogs.msdn.com/b/vcblog/archive/ ... 57555.aspx
In June, we announced enhanced targeting for Windows XP using the Visual Studio 2012 C++ compiler and libraries. This feature has been included in Visual Studio 2012 Update 1 CTP 3.
This new platform toolset points to a repackaged version of the Windows 7 SDK shipped in Visual Studio 2010 instead of the Windows 8 SDK, but uses the same Visual Studio 2012 compiler. The v110_xp toolset also sets useful defaults such as a compatible linker subsystem version for downlevel targeting.