Silver light RIa Services

I have a solution using ria services.   I can load query and fill data grids no problem.  I can Add, Update and Delete. What I cant seem to figure out is how to select a single item from a collection.  

I have tried this on the client but returns nothing
Dim Target = (From T In Ctx.Targets
         Where T.TargetID = OutputTargetLink.FKTargetID
         Select T).FirstOrDefault


i have added this to my domain service but it does not appear to available from the client. Do I have to

    Public Function GetTarget(TargetID As Integer) As Target
        Return Me.ObjectContext.Targets.Where(Function(e) e.TargetID = TargetID).FirstOrDefault
    End Function