Using: umbraco v6.1.0 beta 2 

We're trying to perform some custom validation on PublishingStrategy.Publishing in v6.  

When an error is encountered, we set e.Cancel = true; try to show a speech bubble error and return

Everything is working well except we can't seem to control the speech bubble to display a useful error.  We tried to do this via the old v4 BasePage.Current.ClientTools.ShowSpeechBubble method, but the error doesn't display.  Instead a publishing error displays stating that "Publishing was cancelled by a 3rd party add-in".

What is the v6 function to display and manage the speech bubble?  

Any help is appreciated.

Thanks