Add hidden input dynamically

[furic]

Hello
I'm trying to add hidden input to page dynamically.
The code is executed in the actionListener, wich is fired from link:

<h:commandLink id="editBuilding" action="editBuilding" onclick="openPopup(window,'editBuildingWnd','../',120)" target="editBuildingWnd" actionListener="#{buildingBean.selectObject}">

in the action listener of buildingBean:

public void selectObject(ActionEvent event){
 UIComponent body = FacesContext.getCurrentInstance().getViewRoot().findComponent("bodyTD");
 HtmlInputHidden id = new HtmlInputHidden();
 id.setRendered(true);
 id.setId("objID");
 ValueBinding vb = FacesContext.getCurrentInstance().getApplication().createValueBinding("#{buildingBean.objId}");
 id.setValueBinding("objId",vb);
 body.getChildren().add(id);
}

and the structure of jsp the request is forwarded to is :

<f:view>

<h:form id="popupForm" enctype="multipart/form-data" style="margin:0px; padding:0px" >
<t:htmlTag value="td" id="bodyTD" forceId="true" >
...
</t:htmlTag>
</h:form>

I have few problems here :
1. I get null when i try to find form component like this:
UIComponent body = FacesContext.getCurrentInstance().getViewRoot().findComponent("popupForm");
2. Then i decided to add hidden input to td (bodyTD), it's found , but i don't see hidden input is rendered in html.
Please advise
Thanks