Why will the word "submit" not show up on the interactive PDF I created?

Question

I have created and interactive PDF that works great, in Acrobat 9. All the buttons work. My only problem is that the word "submit' will not appear on the completed form. I have put the word there and when I place the gray button over it, the gray rectangle button covers it and won't let it show through. How do I make the button say the word "Submit?"