How to Consume web service generated in PI server

Hi Experts,

I would like to know the following things in the SOAP Sender scenario.

1) Our scenario is SOAP-PI- Server proxy. To send data to PI server from the external web server , the external web server will use the wsdl file and the URL generated in the PI server ie in the Sender Agreement. Can we share the same URL which is shown when we right click the Sender Agreement-> Display WSDL-> WSDL URL and at the botton the wsdl is shown , to the web server programmer to consume the web service?

2) Also I have come across about publishing the web service in Service registry. Is it mandatory to publish the web service in the Service registry before publishing it for consumption to the external web server?

3) Also would like to know how to fire the SOAP query from SOAP UI test software to SAP PI SOAP Sender Interface for testing purpose. Can somebody share the step by step approach for this?

Thanking You

With Best Regards

Suhas