Microsoft has released .net 4.6

Microsoft .NET Framework 4.6 (Offline Installer) for Windows Vista SP2, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2008 SP2 Windows Server 2008 R2 SP1, Windows Server 2012 and Windows Server 2012 R2

I build .net 4.6 into my custom base image along with Visual C++  :

Download .net 4.6 offline installer from link…

Create a Application into your Build and Capture environment.

Select source

Set a destination name

Enter the silent install command for .net 4.6 : NDP46-KB3045557-x86-x64-AllOS-ENU.exe /passive /norestart

Create the application

Go to you “Build and Capture” Task Sequence and enter the application just created and a restart action just after