consuming enterprise service without ESR nor service registry

Hello experts, iam going to consume an enterprise service directly from SAP ECC6, using webdynpro abap as user interface, reading the documentation on these subjects, i found terms like Enterprise services repository , an services registry, even some times they use SAP PI between the user interface and the backend, ..

¿ is it possible to consume an enterprise service by an abap web dynpro DIRECTLY, without all of that infraestructure?

¿does any body has an example, howto, necessary steps, ?

thanks in advance