Much easier when you've got the right cable!

To get the lcd working you need a special version of lcdproc with the right driver. There's a whole thread on doing this. It's NOT a package you can install from the gui. Read through the thread, it's interesting anyway, before attempting to install it.
I tried to make a more consise set of instructions in my thread (the lcd package is the same for X-peak) and rolled up the newest driver into the tarball
here.
Have you enabled the interface?
Steve