I have a WCF Webservice hosted on IIS which exposes a single method that takes three integer parameters. I have a simple, console based client which can call this method.
Disclaimer: I'm not a WSDL expert, so i can't tell you why the doc doesn't provide detail.
To generate the SOAP envelope for JMeter, I've used the free version of soapUI.
This provides me all the information I need for jmeter, including parameters, user-agent, endpoint, etc.