If you want to make a Solution and Project, for both VS2010 and VS2012, what things you have to change for all to work out without problems?
1. Solution_vs2010.sln with Project_vs2010.vcxproj
2. Rename Solution_vs2010.sln to Solution_vs2012.sln
3. Rename Project_vs2010.vcxproj to Project_vs2012.vcxproj
4. Edit Solution_vs2012.sln and change inside Project_vs2010.vcxproj to Project_vs2012.vcxproj
5. Open Solution_vs2012.sln with VS2012 and let it make conversion
Still there must be something more to change because after opening the converted VS2012 solution/project, there is no code files added like in the 2010 project.