You can find the webservice API's in WebserviceModule. For instance:
WebserviceModule.callWebservice(location, soapAction, soapRequestMessage)
You can use these to build your own webservice requests and fire them. We currently don't have any API's that allow you to call an imported webervice using the mappings in the modeler.
That being said, you could always create a simple microflow which only calls the webservice, and then call that from your java action (I don't see exactly why you would want to call a webservice from a java action, so I don't know if this is a viable workaround for you)
Hi Achiel, thank you for answering. I want to specify the parameters instead of mapping them. Have a look at my previous question, I am battling with the way that Mendix maps mandatory and optional objects and attributes. I'll try the API and reply shortly. Thanks again.