how do I create a form field for a paragraph response?

I'm using Acrobat 8 Pro and I've created a fillable form with one field that requires a somewhat longer response, like maybe a paragraph or two.  I've tried changing the Options to include the check boxes for "Multi-line" and "Scroll long text," but still only one line of text is visible in the field when the form is printed.  How do I make the entire response visible?