Karabiner config file for device specific inverted scroll direction

private.xml

<?xml version="1.0"?>
<root>    
    <devicevendordef>
        <vendorname>Microsoft</vendorname>
        <vendorid>0x045e</vendorid>
    </devicevendordef>
    <deviceproductdef>
        <productname>MicrosoftNanoTransceiverv2_0</productname>
        <productid>0x0745</productid>
    </deviceproductdef>
    <item>
        <name>Microsoft Mouse Scroll</name>
        <identifier>custom</identifier>
        <device_only>DeviceVendor::Microsoft, DeviceProduct::MicrosoftNanoTransceiverv2_0</device_only>
        <autogen>__FlipScrollWheel__ Option::FLIPSCROLLWHEEL_VERTICAL</autogen>
    </item>
</root>

Can you tell me how to use this code with the new Karabiner elements? It seems like private.xml is out and js files are in.
Total noob here. Sorry!