When accessing Silverlight in WCF you get proxies generated with ObservableCollection

Thats fine when you're databinding, but a little clumsy when you're just calling a method. For instance the following service method :

    [OperationContract]
    public SearchOrdersMsgOut SearchOrders(ShippingStatusType[] shippingStatuses,
                                           string[] orderId)
    {
    }

gets generated with ObservableCollection. What! They're just parameters. Why would I ever want to 'observe' them?

I'm fine if I have to do this - but it seems like there should be a way to force simple array structures when I know I'm never databinding - especially on input messages.

I'd much rather do this :

 searchCriteria.PaymentStatus = new [] { PaymentStatusType.PaymentFailed, PaymentStatusType.Unpaid };

than this :

 searchCriteria.PaymentStatus = new ObservableCollection<PaymentStatusType> { PaymentStatusType.PaymentFailed, PaymentStatusType.Unpaid };

Is there a way?

PS. I do actually use a SearchCriteria object for my search criteria - but I simplified for this example wondering if parameters were handled differently.