Web service client with SoapClient == AsynchronousOperationExcepti

[martin]

I'm trying to implement a simple web service client using the SoapClient
class. I need to add support for new web services later without restarting,
let alone recompiling, my application and so generating code using "add web
reference" is not an option for me.

Anyway, while using the SoapClient.SendRequestResponse() method I keep
getting AsynchronousOperationException regardless of which one of my test web
services I use and regardless of what I send to them. Typically I would just
send a simple SOAP envelope that contains "<hello>world</hello>" or something
like that.

The MSDN documentation says that AsynchronousOperationException is thrown
when "the format of a SOAP message is invalid" but exactly what does that
mean? How can I get more specific information about what is wrong with the
SOAP message? And is it a problem with the SOAP message that I send or the
one that I receive as reply?
sincerly,
martin