FIRST Google result: http://www.verboon.info/index.php/2009/10/splitting-and-merging-image-files-with-imagex/ Seems rather easy to me. I still would like to know what your mod program was.
You found a bug! I forgot to add the copy inf section ALL OF IT!!! Please just grab the silent installer and open it with winrar. Copy cplbonus.inf to windows\inf