OK, so to be a good citizen i'll post the answer here because i figured it out.
Eventually i ended up creating a extra class which essentially is just a holder for the entry list.
public class KeyValues extends BaseModel {
@XStreamImplicit(itemFieldName="entry")
private ArrayList<KeyValueEntry> entries;
}
Using the XStreamImplicit i can bind the entry object to my arraylist.
It's not the most pretty solution but it works.