Please help, I've asked a similar question several times and it's never been answered!

Suppose I have an entity like:

@Entity
class Delivery {
 private long id;
 private Map<Date, Integer> amounts;

 @Id @GeneratedValue
 public long getId() {
 return id;
 }

 public void setId(long id) {
 this.id = id;
 }

 @CollectionOfElements
 public Map<Date, Integer> getAmounts() {
 return amounts;
 }

 public void setAmounts(Map<Date, Integer> amounts) {
 this.amounts = amounts;
 }

}

How can I access the "amounts" property in queries?
I'd like to create an aggregate query that gives me a sum of delivered amounts per delivery. How do I do that?
How can I even retrieve the value of "amounts" from a Criteria Query using a Projection?