How to access a Map using playframework template system (groovy)

I've been using the--quite excellent--playframework and have had trouble finding documentation/examples on how to access a Map data structure from a view, using play's template engine.

To be even more specific, I wish to access the Map as I iterate over a List of objects, e.g.,

#{list items:itemList, as:'item'}
 // access the map value using the ${item?.id} as the key
#{/list}

Thank's for looking.