I think I've got it!

So the action sheet did not work for me.  So I tried a couple of different things and now I have the UI that I need.  When the user hits the text box, a picker comes up.  They can then choose the grade, both the letter and the sign. (Yes, I was able to make it a double wheeled picker!) I am going to code everything in this weekend and make sure it runs on both iPhone and iPad.  Although I will need to do a popover view for the picker to work on the iPad.  Hope it all goes smoothly.