Flex runtime error: IManaged

Need some help with fill() and named querys:

1) As long as I use the dataservice.fill() mehod to populate an arraycollection with the results from a simple named query like "SELECT * FROM Book WHERE..." I have no problems and the arraycollection gets populated correctly. But as soon as I use a more complex query like "SELECT l.id, b.title, c.surname, c.telephone, c.email FROM Loan l, Book b, Customer c WHERE..." I get a Flex runtime error that says:

ArgumentError: Items must support IManaged. See [Managed] for more information: object: (Array)#0
[0] "2003100099"
[1] "Da Vinci code"
[2] "Jackson"
[3] "024982363"
[4] "m.jackson@hotmail.com"
at mx.data::ConcreteDataService/http://www.adobe.com/2006/flex/mx/internal::normalize()
at mx.data::DataList/http://www.adobe.com/2006/flex/mx/internal::processSequence()
at mx.data::DataList/http://www.adobe.com/2006/flex/mx/internal::processSequenceResult()
at ::DataListRequestResponder/result()
at mx.rpc::AsyncRequest/acknowledge()
at ::NetConnectionMessageResponder/NetConnectionChannel.as$40:NetConnect ionMessageResponder::resultHandler()
at mx.messaging::MessageResponder/result()

This I think means that the query is executed correctly ( and it retrieves the correct results array i.e. [0] "2003100099" [1] "Da Vinci code" [2] "Jackson" [3] "024982363" [4] "m.jackson@hotmail.com" ) but Flex can't use it to populate the arraycollection: the reason is probably that it gets the data from various sources (Loan, Book, Customer) and so the instance returned is not one of my standard remotely managed pojos.


Riccardo