Rotary axis in Qtdragon_hd

Hi, I am playing with qtdragon_hd and cannot seem to get a fourth rotary axis (XYZB) working in the preview in the way I would like. At the moment, in the simulation samples in the latest 2.9.3 release such as "qtdravon_hd_xyza", the rotary A-axis rotates the spindle. But in my setup, I want to rotate the stock. I've tried changing the "trivkins" in the INI file to other options, but then the machine doesn't even turn on for some reason! Does anyone have a working example they could share where the stock rotates rather than the spindle? Thanks! 

This is awesome! Thank you so much. Who would have thought it would be as easy as adding one character to my INI!

GEOMETRY = ​​​​​​! BXYZ

Thanks again!