<p:rowExpansion>
                <p:dataTable id="expanded" value="#{impressaoBean.listaItens}" var="item" styleClass="processamentoExpanded" >

                    <p:column width="30" style="text-align:center">
                        <h:outputText value="#{item.itemFormatado}" />
                    </p:column>

                    <p:column width="20" style="text-align:center">
                        <h:outputText value="#{item.produtoID.nomeProduto}" />
                    </p:column>

                    <p:column width="20" style="text-align:center">
                        <h:outputText value="#{item.quantidade}" />
                    </p:column>

                    <p:column width="20" style="text-align:center">
                        <p:selectBooleanCheckbox value="#{item.impressoBoolean}"
                            disabled="#{item.impressoBoolean}">
                        </p:selectBooleanCheckbox>
                    </p:column>
                </p:dataTable>
            </p:rowExpansion>

public Boolean getImpressoBoolean(){
    boolean impressoBoolean = false;
    if (impresso == 'S'){
        impressoBoolean = true;
    }
    return impressoBoolean;
}