You can change your localhost setting in your project settings, the mendix runtime will use this value to generate the wsdl (note that you will have to reimport the wsdl). Alternatively, you have the option of using a custom URL in the call webservice microflow activity on the client side.
As far as authentication is concerned, published webservices in mendix require a "web service user" to be present. You can add these by logging in as administrator and clicking the "new webservice user" button in the User menu.
You probably used an constant or specific url in your activity. When you get this exception the message will show the actual url it tries to access. In your case this means that you're receiving the exception: 'java.net.MalformedURLException: no protocol: 2'
This means that the framework tries to access url: '2'
Take a look at your activity and the imported wsdl, maybe you've accidentally checked the box to use a specific url or constant (or selected the wrong one)
Thanks Achiel, seem to be almost there: deployed proj.A (HTTP-port 8081, Server Admin-port 8090) reimported WS and deployed proj.B (HTTP-port 8080, SA-port 8091). Upon running WS-call: “An error has occurred while handling the request. [User 'Anonymous_... with roles 'Administrator']”. In MF properties-allowed roles(proj.A): ‘webgebruiker’ (=module role) coupled to ‘user’ in project security user roles. In proj.B project-security level is turned-off. Why this message?