Seems this sound pack must first be processed in a sample editor such as Creative's "Vienna" to make an .sf2-file of it, otherwise this will not work. I downloaded it, however, I wasn't prepared to go through this lengthy procedure right now. Or do you have an idea of how to get the SI Drum Kit, or Session Drummer, to grab those sounds directly?
I notice of course the wealth of the .rar-file, 4 different versions of closed hihats (for example) suggest 4 different drum sets. So that would mean to sort the sounds to at least 4 different .sf2 sample banks. Sorry, but until I'll be finished with that, my interest in the music project I started will have vanished. It's right, I was looking for an instrument, I did not intend to
build one. ;-)