I've got nothing else? Best guess is somewhere in the registry is a link to what opens up on the taskbar when you open a program? I just don't know where that is? The icon itself is probably within the EXE but under Win7 I can't even change the program icon? It seems for all other programs I can though via the properties, but not for Office programs? Guess this is because of the way it is installed? If I fro drag the program from its folder to the desktop and create a shortcut there, I can change the icon, but it doesn't change what goes on the taskbar? I'd guess that MS has hardwired this or it has to be located in the registry. Hardwired is tougher to find. Somewhere in the exe is a pointer to the icon in the exe to use I guess?
I've got a program, Filealyzer2, you can get it here, and it shows all the icons under PE Resources and the name is RT_ICON in the program with a number for each icon. With this info and a lot of work and a binary editor you might be able to patch the program to show what you want.