The Pronto is just a remote, all they can do is control things that can be controlled by IR
X-10 devices just use your electrical whirring to send and receive signals.
¿Necesito modificar mi instalacion electrica?
depends what you want to do some things just use a normal plugs like

or you might want to replace some switches and sockets like

.
to control your X-10 devices you need an
IR7243 (European version of IR1543)