Zk: Zul Get Value From Input Form-data

I need a help about ZK framework. This is my situation. I have a html page:

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Then, I use following in test.zul

<window apply="org.zkoss.bind.BindComposer" viewModel="@id('vm') @init('test.vm.TestViewModel')">

and then in TestViewModel

@Init
public void init(@ContextParam(ContextType.SESSION) Session session) {
   System.out.println(Executions.getCurrent().getParameter("codigoUnicoCliente"));
}

and work like charm :)