map_in_list_defaults.xml

<?xml version="1.0" encoding="UTF-8" ?>
<routes xmlns="http://symfony.com/schema/routing"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/routing
        http://symfony.com/schema/routing/routing-1.0.xsd">

    <route id="blog" path="/blog">
        <default key="_controller">
            <string>AcmeBlogBundle:Blog:index</string>
        </default>
        <default key="values">
            <list>
                <map>
                    <boolean key="public">true</boolean>
                    <integer key="page">1</integer>
                    <float key="price">3.5</float>
                    <string key="title">foo</string>
                </map>
            </list>
        </default>
    </route>
</routes>