Buttons disappear from custom ribbon when Allow Full Menus is disabled

Question

I've built a custom ribbon and it works fine until I disable Allow Full Menus (File>Options>Current Database>Allow Full Menus). The impact is that two of the buttons disappear from the ribbon - ExportExcel and FileSendAsAttachment. In the same group is PublishToPdfOrEdoc and that appears OK. I've tried changing the IDs but tbh I'm not sure if I have the definitive list. Any ideas what I'm doing wrong?

Here's the XML:

<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui">
    <ribbon startFromScratch="false">
        <tabs>
            <tab idMso="TabAddIns" visible="false"/>
            <tab id="PrintPreview" label="Report Print and View Options">
                <group idMso="GroupPrintPreviewPrintAccess" />
                <group idMso="GroupPageLayoutAccess" />
                <group idMso="GroupZoom" />
                <group id="GroupPrintPreviewData" keytip="x" label="Data Export">
                    <button idMso="ExportExcel" keytip="e" size="large"/>
                    <button idMso="PublishToPdfOrEdoc" keytip="p" size="large"/>
                    <button idMso="FileSendAsAttachment" keytip="m" size="large"/>              
                </group>
                <group idMso="GroupZoom"></group>
                <group id="Exit" keytip="x" label="Exit">
                    <button idMso="PrintPreviewClose" keytip="c" size="large"/>
                </group>
            </tab>
        </tabs>
    </ribbon>
</customUI>