Skipping delivery of publication artifacts within a publication extension

Question

I have a publication made of 3 documents, which is serviced by a post processing plugin.  In certain situations, I'd like to skip the delivery of one or more of these documents from within the post processing plugin.  What is the best way to accomplish this?  I have tried setting the delivery rule expression, but to no avail. 
for (Object inf : artifacts)
    IInfoObject artifact = (IInfoObject)inf;
    props.setProperty("SI_DELIVERY_RULE_EXPRESSION", false);
edit:
The above code is definitely wrong, because that property is only part of processing info within the publication itself.    I also tried the following:
for (Object doc : documents) {
        IInfoObject document = (IInfoObject)doc;
        if (document.getKind().equals(CeKind.CRYSTAL_REPORT)) {
            IProperties piProps = p.getDocumentProcessingInfo(document.getID());
            logger.info("This file should be excluded: " + String.valueOf(piProps.getString("SI_NAME")));
            piProps.setProperty("SI_DELIVERY_RULE_EXPRESSION", false);
            p.setDocumentProcessingInfo(document.getID(), CeKind.CRYSTAL_REPORT, piProps);
Thanks in advance!
-m
Edited by: mja013 on Sep 2, 2009 6:55 PM
Edited by: mja013 on Sep 2, 2009 7:09 PM

Answer 1

Further developments.  The above post looks like I'm going about it in the wrong way.   So I kept looking around, and found that the documentation for the "handle" method within IPublicationPostProcessingPlugin states:
"This method is invoked after the publishing engine has finished personalizing the publication for a particular destination and scope. It must return an IInfoObjects collection containing all the artifacts created by the plugin that will be delivered to the recipients associated with the current destination and scope."
I have returned the list of items I want delivered, but no matter what list I return, I still receive the three original reports in the publication.
Any ideas?  Thanks!
-m