Using MIDI which enables using USB connection.
To use, upload according BitwigTablet.touchosc to TouchOSC device from the editor and copy/symlink TouchOSC/TouchOSC.control.js to ~/Documents/Bitwig Studio/Controller Scripts. Then enable control script on BWS settings (under "saltiolabs" vendor) and choose "BitwigTablet" layout on TouchOSC.
Both layouts use separate control scripts.
Based on TouchOSC layout by Astartes modified by Thomas Helzle.