adding countdown to boot menu

Hi all, I would like to add a countdown timer to the following menu below...say, 5 seconds and if no choice is selected by the user, "c" is auto selected. Can anyone help?

<?xml version="1.0" encoding="UTF-8" ?>
<Config>
    <Menu>
        <Topic Delay="-1">
            <Text>Select an item by using the keyboard:</Text>
        </Topic>
        <Entry Key="1">
            <Text>1. Acronis True Image (64-bit)</Text>
            <LoadKernel>
                <Kernel Arguments="&#32; quiet" Path="dat10.dat" />
                <Ramdisk Path="dat11.dat" />
                <Ramdisk Path="dat12.dat" />
                <Hash Path="sgn13.sgn" />
            </LoadKernel>
        </Entry>
        <Entry Key="2">
            <Text>2. Acronis System Report (64-bit)</Text>
            <LoadKernel>
                <Kernel Arguments="product=system_report quiet" Path="dat14.dat" />
                <Ramdisk Path="dat15.dat" />
                <Ramdisk Path="dat16.dat" />
                <Hash Path="sgn17.sgn" />
            </LoadKernel>
        </Entry>
        <Entry Key="c">
            <Text>c. Continue booting</Text>
            <Chainload />
        </Entry>
    </Menu>
</Config>