6.7.0 - Cant define sheet name with subReport

Hello, I just created a report with 2 subReports inside, the reports work fine, but it cant change the sheet's names to those I especified in the JRXML. Here is the code:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.6.0.final using JasperReports Library version 6.6.0  -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="bradesco-automind" pageWidth="1200" pageHeight="842" columnWidth="1200" leftMargin="0" rightMargin="0" topMargin="0" bottomMargin="0" uuid="49442e48-845e-4448-aeb6-0dc1d6b59170">
    <property name="net.sf.jasperreports.data.adapter" value="AutomindDataAdapter.xml"/>
    <property name="com.jaspersoft.studio.unit." value="pixel"/>
    <property name="com.jaspersoft.studio.unit.pageHeight" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.pageWidth" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.topMargin" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.bottomMargin" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.leftMargin" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.rightMargin" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.columnWidth" value="pixel"/>
    <property name="com.jaspersoft.studio.unit.columnSpacing" value="pixel"/>
    <property name="net.sf.jasperreports.export.xls.one.page.per.sheet" value="true"/>
    <property name="com.jaspersoft.studio.data.defaultdataadapter" value="One Empty Record"/>
    <queryString>
        <![CDATA[]]>
    </queryString>
    <field name="automindCoparticipacaoViewUis" class="java.util.List">
        <fieldDescription><![CDATA[automindCoparticipacaoViewUis]]></fieldDescription>
    </field>
    <field name="automindResumoViewUis" class="java.util.List">
        <fieldDescription><![CDATA[automindResumoViewUis]]></fieldDescription>
    </field>
    <field name="ano" class="java.lang.Integer">
        <fieldDescription><![CDATA[ano]]></fieldDescription>
    </field>
    <field name="mes" class="java.lang.Integer">
        <fieldDescription><![CDATA[mes]]></fieldDescription>
    </field>
    <background>
        <band splitType="Stretch"/>
    </background>
    <detail>
        <band height="131" splitType="Stretch">
            <subreport>
                <reportElement x="1" y="0" width="1159" height="60" uuid="be2da39b-0166-45d4-82f4-2352168f13e2">
                    <property name="com.jaspersoft.studio.element.name" value="Coparticipação"/>
                    <propertyExpression name="net.sf.jasperreports.export.xls.sheet.name"><![CDATA[CONCATENATE("Coparticipação ",T($F{mes}),"/",T($F{ano}))]]></propertyExpression>
                </reportElement>
                <dataSourceExpression><![CDATA[$F{automindCoparticipacaoViewUis}]]></dataSourceExpression>
                <subreportExpression><![CDATA["src/main/resources/bradesco-automindCoparticipacao.jasper"]]></subreportExpression>
            </subreport>
            <break>
                <reportElement x="0" y="70" width="97" height="1" uuid="68744d19-e222-48a2-b26d-2c986ce15995"/>
            </break>
            <subreport>
                <reportElement x="0" y="80" width="529" height="50" uuid="fe534c14-d4e0-4c43-9185-c5c3a8df050c">
                    <property name="com.jaspersoft.studio.element.name" value="Rateio"/>
                    <property name="net.sf.jasperreports.export.xls.sheet.name" value="Rateio"/>
                </reportElement>
                <dataSourceExpression><![CDATA[$F{automindResumoViewUis}]]></dataSourceExpression>
                <subreportExpression><![CDATA["src/main/resources/bradesco-automindResumo.jasper"]]></subreportExpression>
            </subreport>
        </band>
    </detail>
</jasperReport>