Does anyone know how to put in a variable in an open social data situation

<script xmlns:os="http://ns.opensocial.org/2008/markup" type="text/os-data" >
<os:HttpRequest key="yql" href="${variable}"/>
</script>

can you change it to this

<script xmlns:os="http://ns.opensocial.org/2008/markup" type="text/os-data" autoUpdate="true" >
<os:HttpRequest key="yql" href="${variable}"/>
</script>

to allow for modulating data definitions in the os/data or does os-data only work with static situations , like so

<script xmlns:os="http://ns.opensocial.org/2008/markup" type="text/os-data" >
<os:HttpRequest key="yql" href="http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20answers.search%20where%20query%3D%22cars%22%20and%20type%3D%22resolved%22&format=json"/>
</script>

yql is the key you use in the template?