Okay, I think I've searched all of the documentation and the Forum to the point where I cannot find the answer. And, as always, it will be right under my nose.
I just switched from Marimba to Sus. Cym. and when I enter a ";Loud Hit with Mallet"; all I get is a Fat Choke. No manner of humoring the note through all the usual tricks is yielding the proper result. I've checked the mapping diagrams several times and it looks like I have the correct notehead, etc.