Question about control current from Arduino bipolar motor shield?

How to control current from Arduino bipolar motor shield?I have the DRI0023 stepper motor shield for the Arduino and the current is set inconveniently high, at 1.6 amps per coil. I have a 1.2 amp max current motor. Is there any way to reduce the peak current? Is the reference pin brought out somewhere? My motor is 3 ohms per coil, so I can't just turn down the voltage