Java Development Tools

I'm trying to consume a web service for a system called Magento.

The problem I'm running into is that they have a method which called "call" and it takes as parameter a method name. Based on that, the response will be of an entirely different structure. It could return an array, an array of maps, or a simple integer.

It's declared as type xsd:anyType. So when I created the proxy from the WSDL, I just got a stub that return a java.lang.Object.

When I run it, I was hoping that I would just get the RAW XML or something and then I could manually parse it but it just returns an exception.

java.rmi.RemoteException: internal error: no builtin runtime type for com.bea.staxb.buildtime.internal.bts.BuiltinBindingType[java.lang.Object[]; t=Array@http://schemas.xmlsoap.org/soap/encoding/]; nested exception is:
java.lang.AssertionError: internal error: no builtin runtime type for com.bea.staxb.buildtime.internal.bts.BuiltinBindingType[java.lang.Object[]; t=Array@http://schemas.xmlsoap.org/soap/encoding/]

I'm thinking that what I need to do is to create a mapping for each of the different types of call and define how they should be cast, but I can't find any documentation on that or even if that's possible.

The documentation for consuming a web service on:
Oracle® Fusion Middleware
Fusion Developer's Guide for Oracle Application Development
Framework
11g Release 1 (11.1.1)
B31974-04

is severely limited.