I'm pretty sure you will not be able to build from just the ADK - you will also need a range of files corresponding to your WinPE (ADK) version - using the same codebase. You will also require part of the registry from Windows installation media.
MistyPE/Mini-WinFE can use the ADK in conjunction with Windows media to build a 64-bit WinPE with SysWOW64 - this way you can also add packages to the build (e.g. WinPE-NetFx) - see here
Unfortunately I do not have the time to plough through my code to identify all the required files and registry settings for adding SysWOW64 to an ADK build - I have other commitments at the moment. I adapted the settings from the 5-Wow64.script (developed by JFX, Lancelot, 2aCD, ChrisR, etc).