>Error returned is:"Client: Incorrect number parameters supplied for SOAP request
> HRESULT = 0x80070057: The parameter is incorrect..."

When I had those situations when everything was correct as per the Web Service definition, when it started to act like that after a while, I simply restarted the IIS server with IISReset /Restart. I have seen some weird situation that I was able to resolve simply by doing this. I don't know if that will help. But, it might worth the try. I am assuming you started to get this behavior while it was working ok before.