StrawsonDesign Robotic Cape motor control

Hi guys,
I wonder whether to buy this cape as I want to control Stepper Motors instead of DC motors as featured for this cape.
I believe with 4x full H-Bridges I should be able to connect to two Stepper motors max (each motors has two phases wingdings, each winding needs 1 full H-Bridge).
But the code might not have the libraries for a stepper.
So I wonder whether you guys have used the cape with stepper motors already, and if not, you think it would be easy to re-code for Stepper control.
Basically, whilst for a DC motor a constant speed correspond to a constant voltage corresponding to a constant PWM ratio, for a Stepper motor instead a constant speed correspond to a continuous sinusoidal PWM ratio but the winding current measurement must close the control loop, because for a stepper we control the motor current instead of the motor voltage.

Thanks for your feedback if you have a clue.