We sometimes get cases where EWS is being used from a language we don't support (e.g. Java). In such cases, we can support the actual SOAP conversation (i.e. the raw requests/responses between the client and EWS). To do this, we need to have the actual SOAP requests, and more importantly an application that can send these directly to Exchange.
When I had my first such case, I spent a little time looking for a SOAP test suite. I did find a few, but they didn't work very well or required rather more of a learning curve than I was prepared to climb. All I need is a program in which I can enter my SOAP requests and see the response (or error). So, I wrote such a program, which turned out not to take too long. I modified this recently to support other useful functions (though I have only implemented ConvertID, as this is what I needed). I may add more tools to it as needed.
So, I thought I'd make it available here for general use. It is very simple, and perfect for testing Exchange Web Services. I think it is pretty much error-trapped now, though this may not be the case and as always there are no warranties!
The full solution (source and binaries) is now available on Codeplex: http://soape.codeplex.com/. Screenshot of what to expect is below.