While this isn't a convenient solution, as is always the case with such programs, there are unofficial work-arounds. You could always Shift-X to enter a text item, find the character you need from the SMuFL library online and copy and past it into the text box and convert the format to music text and then you could place it exactly as you want. Sometimes you do what you have to to make it look right even if it isn't the "correct" way to make the program understand it semantically.
Here is the character code you need: U+E4AC https://w3c.github.io/smufl/gitbook/tab ... ation.html
I had to do this same process for a different symbol I wanted and it worked just fine.