Three options come to mind.
1. Create the text as an image, add it to an object/button & adjust the opacity of the object/button.
2. Create a display object text & link it to a button or scene object. Same deal as before, adjust opacity of the object/button the text is linked to.
3. Use Lua draw to draw the text, or use the textPane function, however those are both more complicated to use & require scripting.