New
#770
Looks like we are out of luck. All the other files can be found in UUP - either in ISOFOLDER\sources, or in winre.wim\system32. Testplugin.dll seems completely absent from UUP files.It is part of the imagebasedsetup-media package in the real boot.wim.Seems only available from the full ESD dowload.
Simplest alternative is to drop a menu into fake boot.wim\system32, plus a partitioner (bootice or PW etc) and something to apply the image ( dismgui or dism++ etc.)