JAX-WS and RPC/encoded web services.
Since RPC/encoded binding style is not compliant with WS-I Basic Profile 1.1, JAX-WS clients are not able to access RPC/encoded endpoints easily. In another words, the wsimport utility, that is primarily used in IDE, doesn't work for RPC/encoded services.
To access those services the JAX-WS's Dispatch interface can be used. This approach is not so straightforward as the usage of wsimport utility and implementation requires some experience with SAAJ API or JAXB.
See the Jitendra Kotamraju's blog: Accessing Google Web Service using JAX-WS.
JAX-RPC and RPC/encoded binding style
JAX-RPC naturally supports the rpc/encoded binding style, so another option to access RPC/encoded web service is installing JAX-RPC Web Services plugin in Plugin Manager.