HELP using ZK & MVC patterns

<zk>
<window title="composer1 example" border="normal" width="300px" use="org.atos.inicio.controller.Control">
    <grid>
        <rows>
            <row>First Name: <textbox id="firstName" forward="onChange=onFirstName"/></row>
            <row>Last Name: <textbox id="lastName" forward="onChange=onLastName"/></row>
            <row>Full Name: <label id="fullName"/></row>
            <row><button label="OK" forward="onLogin" /><button label="Cancel" /></row>
    	 </rows>
    </grid>
   </window>
</zk>

public class Control extends Window implements AfterCompose{

    private Textbox firstName;
    private Textbox lastName;
    private Label fullName;
    protected PruebaModelBusiness pmb;

    //-- AfterCompose --//
    public void afterCompose() {
           //wire variables
        Components.wireVariables(this, this);
        //NO need to register onXxx event listeners
        //auto forward
        Components.addForwards(this, this);
    }

    public void onChange$firstName(Event event) { 
        fullName.setValue(firstName.getValue()+" "+lastName.getValue());
    }
    
    public void onChange$lastName(Event event) {
        fullName.setValue(firstName.getValue()+" "+lastName.getValue());
    }
    
    public void onLogin() {  
	 	System.out.println("hemos llegado aqui");
		pmb.escribeLogin("aa", "bb");
	 	try {
	 		 System.out.println("user + pswd: "+firstName.getValue()+" "+lastName.getValue());
	 		 Executions.getCurrent().sendRedirect("prueba.zul");
			//win.doModal();
		} catch (Exception e) {
		 	System.out.println("hemos llegado error");
		}
  // refresh UI
  }  
}

package org.atos.inicio.model;

public class PruebaModelBusinessImpl implements PruebaModelBusiness {

	protected PruebaModelBusiness _pmb;
	
	public PruebaModelBusinessImpl(){
		_pmb=this;	
	}
	
	@Override
	public void escribeLogin(String Name, String Password) {
			System.out.println("El nombre y password"+ Name+" "+Password);
	}	
}