Put your BookShop.jar in JBOSS_HOME/server/.../deploy to deploy it into EJB container.
You can annoate your ejb bean using @RemoteBinding:
for example:
@Stateless
@RemoteBinding(jndiBinding = "/BookShop/OperazioniUtenti/remote")
public class TesBean implements ....
and after that you may use lookup inside your sevlet:
initialContext.lookup("/BookShop/OperazioniUtenti/remote");