Cannot mock simple object array with JustMock

I'm using JustMock and AutoFac and trying to mock an array of a quite simple objects but I just can't seem to get the syntax right...

        var labResults = Mock.Create<LabResult[]>();

        Mock.Arrange(() => labResults).Returns(new LabResult[]
                                       {
                                           new LabResult
                                           {
                                               EstablishmentID = "0101",
                                               PatientID = "A11111111",
                                               EpisodeNo = 1,
                                               LabNumber = "975310A",
                                               Status = LabResultStatus.Initial,
                                               TestCode = "ABCD",
                                               DateUpdated = DateTime.Now
                                           },

                                           < snip >

                                           new LabResult
                                           {
                                               EstablishmentID = "0101",
                                               PatientID = "A11111112",
                                               EpisodeNo = 1,
                                               LabNumber = "975310A",
                                               Status = LabResultStatus.Final,
                                               TestCode = "ABC",
                                               DateUpdated = DateTime.Now
                                           },
                                   });

The code compiles fine but when run gives me a 'System.ArgumentException' error on the Mock.Create call - 'Additional information: Value was invalid'.

This one's had me stumped all morning and I cannot find a suitable example anywhere. Can someone please tell me the correct syntax - it needs to be an array that comes back, not a List.

Cheers