Passing expressions and values to a custom datasource.
Is it possible for an expression to be evaluated from one datasource (the xml stream currently used to generate a report), and the resulting value (ie: the text for the specified attribute) to be passed to a custom datasource to display the image?
No. It could be hacked but it would not be a good idea. What they should do is create the image and pass that in in a small xml file they create on the fly as a 2nd datasource.