Designer 8.0 - How to define XML output template type?

I’m moving from WebMethods 7.1 do 8.1.
On WebMethod 7.1 I was able to define the output template type for a flow to xml.
I need to do this on 8.0 but I didn’t found how?

How can I do that?

I’ve tried on Developer 8.0, set the output template to xml but when I run it from a Browser I receive an error. The type is XML but I receive an HTML body inside it.