Hi,
Mach4 is really two programs, Mach4Core.exe and Mach4GUI.exe.
The XHC controller does not support Mach4GUI.exe, it runs instead xwMach.exe which is a very stripped down, bare bones User Interface.
Many features of Mach are unavailable with that interface but are fully and readily available to Mach4GUI.exe. I believe the problem that you
cannot set 'Mach4' because that is non-changeable feature of wxMach.
If you want to get the most from Mach4 then you'll need a controller, or rather a controller plugin, that supports MachGUI.exe.
All the US an European made controllers do so, the one lone Chinese controller, XHC, does not.
Craig