[PD] PD, xxxduino and adafruitmotor shield

[JNM]

Salut

We are in Dakar, Sénégal, for the second PD/XXXduino 
workshop in west Africa where we prototype a suitcase for 
the pedagogy of interactive art.(( 
http://www.craslab.org/valise (draft, english soon)))

We try to find a solution to control the stepper motor and 
dc motor with PD standard firmata 2.1 with the 
adafruitmotorshield. Servomotors are easy to pilot from 
PD, but steppers and DC motor are piloted by a chip.
The docs says 
(http://www.ladyada.net/make/mshield/faq.html):

  "The DC/Stepper motors are NOT connected to the Arduino 
directly. They are connected to the 74HC595 latch which is 
spoken to by the Arduino. You CANNOT talk directly to the 
motors, you MUST use the motor shield library"

Does anyone in the list has found a hack to talk to this 
chip from PD to pilot the steppers and DC motors ?
Thanks
JNM, Jérôme Abel, and 17 Senegalese and Malian students