Using the '+' sign in Lyrics

As a teacher, I like to use the '+' (plus sign) to write in the counts in Lyrics mode, of a particular rhythm. (eighth notes being counted as '1 + 2 + 3 + 4 +.' The plus sign disappears when I type it in. I don't want to use the '&' sign because that confuses the younger kids.

Please add functionality to use the '+' in Lyric mode.