Hi Bas-l,
read the thread. it's basically all in there. the way i did it ( and how it worked for me) was basically like on the diagram and in the code. you just have to make sure that the voltage is around 3,3V max on the dipsplay.
i'd really like to help you more. But i gave away my prototype (it was a gift) and back then i didn't think it was necessary to document it... well.
i still have some displays around. i hope i'll find the time to do it again.
the code works though.
good luck,
kuk