Hi JavaK,
I just tried this and I had no issues creating the instance. When you assign the variable, are you simply selecting the var to be a ‘.NET Class’ and then selecting the System.IO.StringWriter class?
Just another thought, but if you need to change the message to a string, why not assign the incoming message to a System.Xml.XmlDocument and use the .InnerXml or .InnerText to get your data? Unless, of course, you’re not wanting to use those….just wanted to offer anything to help.
-Rich