Perhaps the fact that I was surprised that the article's author didn't immediately think of Fiddler is evidence of how exclusively I've worked with web services via .NET. Personally, I've had a great experience with SOAP from within Visual Studio. Once the service reference is established, all coding is against the strongly-typed code-generated classes. If I must, I use Fiddler to debug. My experience has been positive.
No Windows boxes round these parts, or I would have. I tried WebScarab, but without the server certificate it was a lost cause (unless I missed a trick somewhere).
You have to generate a certificate for the proxy (WebScarab) and have the client trust it. The proxy will then act as a man-in-the-middle, presenting its own certificate to the client. See: