Use a symbol font such as webdings.
I installed the symbol font in FMP10Adv, but how do I get to the character map to select one? I can't find anything in FM Help on this.
I think you'd have to make your own. You could, for example, use New Window to pop up a window and put a button with the appropriate symbol font text on each button and then a script that inserts the character shown on the button into the text field of the underlying window. (Each button can pass a different character to the same insertion script as a script parameter.)