Unable to use enlarged drumkits

I want to use some brush sounds for soft jazz. All the tutorials for this that I have seen show using "drumset" as the instrument selection. This drumset instrument isn't present in my installation of MueScore. So, I select "large drum kit." I can pick soundfonts or a VSTi, but it still only plays the same selection of sounds that are available in the "large drum kit," even if I try to add some sounds in edit drums. To clarify, with the soundfount or a VSTi, I can make the tom or the bass drum, for example, sound different, but I don't get the additional sounds such as the brushes. In my preferred VSTi, this is supposed to be note D#1. When editing the drumkit, it will let me give that note a name, and it will let me put the note on the staff, but when I click the note or click play, it is silent. VSTi sounds for drums included with the default "large drum kit" do sound. So, the VSTi is working. What to do?
I am using version 4.4.2. I can upload screenshots if needed, but I hope I've described it adequately.