Has anyone figured out how to present a message to the user with the new JAVA PX's?

 I would like to present a message window to the Agile user (Very similar to the routine messages Agile dispalys) that would give them immediate feedback in the gui if they make a mistake when entering data or pushing a workflow. Currently we only seem to be able to send e-mail or log it in the History tab, but I want to pop up a text box with a message. I understand that I can throw an error/stop and display that, but it seems like a crude way to communicate. Is there a way to call a sub routine like