driving STEVAL-IHM023V2 without controller

We are working with the STEVAL-IHM023V2 to drive a brushless DC motor of 24V. The set up is to be used in an academic environment and will be used as set up for students. As it is their task to make the control algorithm (from current set point to switching pattern based on Hall sensors) we did not buy the controller of ST. The tests we did so far were successful but it is not possible to keep one leg of the inverter open (in a stable way). The only way we found so far to keep both upper and lower switch open was to keep both connection points floating (which cannot be the right option). Is there anyone who has tried to do the same and knows a solution?