I stumbled upon this thread while trying to solve this exact same issue. Seems like this thread wasn't a success. But I finally solved it, if you're still wondering, here's: 
	 
	-Select the concerned cymbal by clicking on it
 
	-Above the drum picture, in the right  corner, select the ''tail mute'' articulation  that's under ''Not-MIDI mapped''. Now we need to MIDI-map it
 
	-In the edit column that's further on the right, double click on the ''MIDI mapping'' tab. You should see the ''tail mute'' entry
 
	-Click on the 3 horizontal line logo next to the ''tail mute'' entry
 
	-Select either ''learn'' or ''map'' according to your preference 
	 
	Now you can play or map the mute as a note.  
	 
	There you go! Let me know if that helped