You may have better luck with the datasheet for the controller which I believe is an SED1330. Certainly the quality of the printing will be better than the one I found for the HG25504 at All Electronics.
I believe there is a total of 31 pins available on this board (I don't have it in front of me right now). But I have only been using pins 1 - 17 which is how many pins are on the datasheet. There is an obvious distinction between pins 1-17 and 18-31. Does the HG25504 handle pins 1 - 17 and the SED1330 controls 18-31?