How to index for nested date in RavenDB

Perhaps I generally bark for what's wrong here, but ... I have a RavenDB with a lot of objects like RavenPerson.

Each RavenPerson has a list of mail bodies, each of which has an associated date.

{
  "Bodies": [
    {
      "RenewalRunDate": "2011-11-30T00:00:00.0000000+00:00",
      "BodyText": "A bunch of text"
    }
  ]
}

I want to take the given date and get a list of the person’s identifier and the body text associated with it.

So...

    public class MailingsByDate : AbstractIndexCreationTask<RavenPerson, PersonMailingModel>
    {
        public MailingsByDate()
        {
            Map = people =>
                  people.SelectMany(person => person.Bodies,
                                    (person, body) =>
                                    new PersonMailingModel
                                        {
                                            MembershipNumber = person.MembershipNumber,
                                            MailingBody = body.BodyText,
                                            MailingDate = body.RenewalRunDate
                                        });
        }
    }

but when i call it

        var mailings = DocumentSession.Query<PersonMailingModel, MvcApplication.MailingsByDate>()
                                      .Where(pmm => pmm.MailingDate == date.Value);

I get an exception

Cannot apply object of type "IntegraRenewalMailLibrary.RavenPerson" type "RenewalLogs.Models.PersonMailingModel".

Thanks in advance!

Update: Changing the index call as shown below does not eliminate the exception

        var mailings = DocumentSession.Query<PersonMailingModel, MvcApplication.MailingsByDate>()
                                      .Where(pmm => pmm.MailingDate == date.Value)
                                      .As<PersonMailingModel>()
                                      .ToList();

Update to update: I created a visual studio solution with sample tests here: https://github.com/pauldambra/IndexExploration

1.0.888

, , , , ...

, SelectMany linq

    public class RecipientsByDate : AbstractIndexCreationTask<Person, PersonMailing>
    {
        public RecipientsByDate()
        {
            Map = people => from person in people
                            from body in person.Bodies
                            select new PersonMailing
                                       {
                                           MembershipNumber = person.MembershipNumber,
                                           MailingBody = body.BodyText,
                                           MailingDate = body.MailingDate
                                       };

        }
    }