From my co-worker, Patrick Dawson, via email:
I think the following article is very helpful to anyone who is trying to learn about how to write custom Java methods to be used with Documentum workflows.  It’s also interesting because its sample code transforms an XML source document dropped into a workflow package.  Finally, the sample code uses the source document’s keywords to pass parameter values into the Java code.  The parameter discussed in the example indicates whether the XSLT transformation output should be stored as a rendition, as an improted object in the docbase, or on the local file system.