Build NuGet package for multiple framework targets from Visual Studio 2010 project file

Internally within my organisation we maintain a code library, some of our applications are built on .NET 4 while older applications are still built on .NET 3.5.

We have build configurations that target either the .NET 4 or .NET 3.5 framework and thi开发者_如何转开发s works as expected. We hit a problem when we want to build NuGet packages that include the output from each build configuration into a single nupkg file (since a NuGet package can support multiple framework targets).

Has anybody come up with a solution to automate this scenario?

After having a good look around I found my solution by looking at how the Autofac project handled the problem.

From this I have built a solution using MSBuild.