My Team are evaluation to a bigger Business portal. (Invoicing, Bookkeeping, Salaries.....)

We are all used to work with DDD, O/R mappers with NHibernate as our first choice. We have chosen to work with CompositeWPF to keep modularity between all modules and part system in the business portal.

Now we have evaluated Ria Services and are kind of disappointed how it works in a Data Oriented way, Data Oriented can be good in a service oriented scenario, but we feel that we can with an Object Oriented approach to, and we feel that we can get an application with less complexity with the OO approach than the DO approach. For example it doesn't allow Value Objects, Many-to-many relations, everything needs to have keys and so on.

We haven't looked at WCF Data Services yet so our question is WCF Data Services our answere? Does it integrate good with Silverlight 4? Can we work with it in a OO manor?