Notating Pedal Changes via custom palette symbol

In a much previous version of musescore, I was able to create custom palette symbols for each note letter and a corresponding sharp, flat, or natural. (so, one for A flat, one for A natural and one for A sharp, each in black and red. And so on, for each letter of the musical alphabet.) So when I wanted to insert a pedal change notation, all I had to do was select a note, double click on the desired symbol/letter in the palette, and the desired pedal change notation would appear below the note. I haven't been able to figure out how to do this in musescore 3. I would love to have this feature again (if it exists already, please point me in the right direction!). I have found, and installed, the pedal diagram plugin, and it works well. But this is not what I am talking about here. Let's say I want a Bb (b flat) below the score at the moment the B pedal needs to be moved to the flat position. Instead of having to insert text, then remember the shortcut to get a flat, natural or sharp into the text, I would like the Bb to show up as a palette item. Or, if there is another, easier way to notate pedal changes, please explain to me how. Thank you!