There is no inch pp for Axiom. That is because the controller only works in metric, no "change to inch" command.
That said, you don't need one. You can make anything you want in Vectric software in either Imperial or Metric. If you design in Imperial, the software does the Imperial/Metric conversion for you when it creates the Gcode. The only time you have to deal with metric is when you input directly into the handheld, i.e. move X+ 10mm, Z up 20mm, or zero the XY @ 300mm ,582mm.
You want to run 'Axiom HHC CNC (mm) (*.mmg)'.