<h:outputLabel for="username" value="Email" />
<p:inputText id="username" required="true"
    label="Informe seu email" value="#{securityController.email}" />

<h:outputLabel for="password" value="Senha" />
<p:password id="password" required="true"
    label="Informe sua senha" value="#{securityController.password}" />

<p:spacer />
<p:commandButton process="username password @this" value="Logar"
    id="botaoLogar" update="msgs" ajax="false"
    styleClass="ms-botao-login ms-cor-botao"
    action="#{securityController.processaLogin()}" />

@Named
@SessionScoped
public class SecurityController implements Serializable {

    private static final long serialVersionUID = 1L;

    private String email;
    private String password;


    public void processaLogin() throws ServletException, IOException{
        FacesUtil.redireciona("/spring_security_check");
    }

    public void preRender(){
        FacesContext facesContext = FacesContext.getCurrentInstance();
        HttpServletRequest request = ((HttpServletRequest) facesContext.getExternalContext().getRequest());

        String user__ = request.getParameter("user__");
        String pass__ = request.getParameter("pass__");

        this.email = user__;
        this.password = pass__;

   // gets and sets

}