How to expose an iterator variable from a JSF composite component to the IDE in the using page - eclipse

Question

My setup is Eclipse Oxygen, JSF 2.2, JBoss 7.0 (Mojarra JSF implementation) and Primefaces 6.0.
I've wrapped the Primefaces dataTable in a JSF composite-component (my:dataTable):
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://xmlns.jcp.org/jsf/core" xmlns:h="http://xmlns.jcp.org/jsf/html" xmlns:p="http://primefaces.org/ui"
xmlns:pt="http://xmlns.jcp.org/jsf/passthrough" xmlns:composite="http://xmlns.jcp.org/jsf/composite"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<composite:interface>
<composite:attribute name="value" required="true" type="java.lang.Object" />
<composite:attribute name="var" required="true" type="java.lang.String" targets="dataTable"/>
</composite:interface>
<composite:implementation>
<div class="ui-g">
<div class="ui-g-12">
<p:dataTable id="dataTable" value="#{cc.attrs.value}" sortMode="multiple"
paginator="true" rows="10"
rowsPerPageTemplate="10, 20, 50, 100" currentPageReportTemplate="Ergebnisse {startRecord} - {endRecord} von {totalRecords}"
paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}">
<c:set target="#{component}" property="var" value="#{cc.attrs.var}"/>
<composite:insertChildren/>
</p:dataTable>
</div>
</div>
</composite:implementation>
The Primefaces column is implemented as a custom component (my:column):
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://xmlns.jcp.org/jsf/core" xmlns:h="http://xmlns.jcp.org/jsf/html" xmlns:p="http://primefaces.org/ui"
xmlns:pt="http://xmlns.jcp.org/jsf/passthrough" >
<p:column headerText="#{headerText}" sortable="#{sortable}">
<ui:insert />
</p:column>
</ui:composition>
And the component is called in the using page:
<my:dataTable id="datenTabelleID" value="#{showcaseDatenTabelleBean.quellWerteListe}" var="laufvar">
<my:column headerText="ID">
<h:outputText value="#{laufvar.id}" />
</my:column>
<my:column headerText="Name">
<h:outputText value="#{laufvar.name}" />
</my:column>
</my:dataTable>
Everything works as expected except for the IDE (in my case Eclipse) code assist for the iterator variable. I have no code completion for the attribute declared as var (laufvar).
Thanks in advance.