vs2015 msbuild

Not sure if it's the right place for the question, but here it goes:

I installed Vs2015, and everything looks cool.  Then I want to setup a build environment on my build server.  I copied the MSBuild\14.0 folder from my VS 2015 machine to the build server, but the MSBuild won't run. It ask for a System.Threading.Tasks.Dataflow dll.

So copied that file over, it worked, but it uses the old CSC, i.e. the one under .Net 4.0.3019

I need it to use the csc2 under the 14.0 folder.

Who got it to work?