Well...I found a work around. Basically I ran this script twice...the
first time my appearance used a white blank JPG as I found out that they
do not support transparency and the second run was what I actually
wanted to show. So in a nut shell, I covered up old PDF text with a
white jpg appearance, then covered the jpg with a PDF appearance.
Still...would prefer to know the script way of changing the field to a
fill of white.