Xan,
It’s been a long time since I’ve checked these forums. I have figured out how to use the Serial mode of the display. On the back of the display you need to remove the 0 ohm resistor at J3 and then solder J4. I have a picture of the modification.
There’s also a really great library that uses this display in serial mode. Here’s the link code.google.com/p/u8glib/
The downside is that this library takes up a lot of space which doesn’t leave room for very much code.