SelectItem listbox in ZK framework

I have this code in ZK:

<zk xmlns="http://www.zkoss.org/2005/zul">    

 <window id="CreateList" border="normal" mode="modal" width="320px"
            apply="org.zkoss.bind.BindComposer"
            viewModel="@id('vm') @init('UserMno')">
    <label value="First Name"></label>
    <listbox model="@bind(vm.allMno)" checkmark="true" multiple="true" selectedItem="@bind(vm.mnoList)"/>
    <button id="closeBtn" hflex="1" label="close" onClick="CreateList.detach()" />
</window>

</zk>

And the idea is i have a list with users and if a click in a user, it have a collection of Mno, and when i open a new page all my Mno must to be load in a listbox, but the mno of the User must to be checked

And i have in Java a class with my viewModel, and is:

public class UserMno {

Collection<String> mnoList;
Collection<String> allMno = MnoDAO.getAllMnosByName();

public Collection<String> getMnoList() {
    return mnoList;
}

public void setMnoList(Collection<String> mnoList) {
    this.mnoList = mnoList;
}

public Collection<String> getAllMno() {
    return allMno;
}

public void setAllMno(Collection<String> allMno) {
    this.allMno = allMno;
}


@AfterCompose
public void initSetup(@ExecutionArgParam("mnoList") Collection<String> mnoList) {
    this.mnoList=mnoList;
}


}

And the java where i pass the user is:

@Command
public void showModal(@BindingParam("languageContributionStatus") UserStatus mnoList) {
    //create a window programmatically and use it as a modal dialog.
    final HashMap<String, Object> map = new HashMap<String, Object>();
    setPickedItemSet(mnoList.getMnoList());
    map.put("mnoList", mnoList.getMnoList());
        win = (Window) Executions.createComponents("/com.users/CreateMnosUser.zul", null, map);
        win.doModal();

}

UserStatus is a class with a collection of Mno, and when i select a user, my user is: mnoList.

Then The idea is:

I have a list of users in a page, and i need load a page, and in that page, i need load a list that the user mno that the user has associated.

But my listbox never load my collection with my selected item. And i do not know, what happen =(.

Can somebody help me?

As you have set multiple="true" you need to use selectedItems (with an s) not selectedItem.

Also I believe you need to init your mnoList Collection:

Collection<String> mnoList = new HashSet<String>();