Pick a Note

Hi everyone!

I am a bit stuck. I want to have a place where I can say "pick a note", so that the player, in effect, chose any note at random to play for that value.
So I went to text --> staff text and edited it to say "pick a note". That part is fine.
But the problem comes in where I want to change the notehead so that it looks like an 'x', or a ghost note.
I can't seem to replace the round notehead with an x. It's not for a percussion part.
So I went to the master palette, double clicked on the note, and then clicked the x. So it appeared, but the normal note head did not disappear. How do I change that?

Is there maybe a different way of depicting what I want to accomplish? Am I barking up the wrong tree with the ghost note?

Thank you for any and all help. :)