If you do not handle the error in the webservce's code ie, try and catch block then it should bubble up though to the smartobject and workflow as long as there's no error handling in between them either. Another method, like the earlier post suggested, woud be to add a code event after the event where you put the result in the data dield. Then right click on the event and click view code. In there put in.if datafield = error or something " throw new exception("some error mesage")". This will throw a error in the workflow and you will see it in workpace. As long as you dont have a process wide error handling setup for the whole process it should work.