Xfce volume icon

I am trying to replace the volume icon in the panel of Xfce 4.18.1 with the one that doesn't look like the stock plain one. In MX-21 this was easy as all I had to do is put this volumeicon command in Session and Startup which would show a nice sound icon. In MX-23.1 Xfce this doesn't seem to work. The volumeicon command works if I put it in the terminal but goes away as soon as I close the terminal. How can I get this icon to show on startup?