If I remember correctly, one of the demos had a conditional view on the text object that has the image behind the chart or in the chart itself. Removing that condition you are able to see the image as well.
Anyway, if you can point as to the file we chan take a look as well.
Hope that helps.
Funnily enough I have managed to find a reply you gave to someone else on the same topic (turns out searching on 'google map' gives better results than searching on 'google maps'!):
The code that has the reference to the google map image needed to be changed to remove some of the formatting and the Transparency needed to be set to 0 as opposed to 100 (otherwise it wouldn't show).
Thanks for the reply,