Setting workflow transition comments with web service

I’m using the Rhythmyx web service client 6.0.0 jar to make updates from a java program. Some of the items I’m updating are in a public workflow state and I need to transition them to an editable state then transition them back when I’m done. I’m able to successfully transition them away from public to the new version using com.percussion.webservices.system.System.transitionItems(TransitionItemsRequest transitionItemsRequest).

The problem I’m having is that the transition back to public requires a comment. I get a web service fault with the message:

com.percussion.workflow.PSTransitionException: A valid transition comment was required but not specified… (error code 1,108)

I don’t see anywhere in the API that I can specify a transition comment. The request object only takes an array of ids and the transition name.

How can I set the transition comment using the web service client?