An update to .NET 3.5 SP1 has been recently released, you can search for KB959209 in the Microsoft Knowledgebase. Here is a direct link to the article: http://support.microsoft.com/kb/959209. This update is important for Dynamic Data users that are using the Entity Framework as it corrects the problem that the RTM version of Dynamic Data had with certain types of relationships with Entity Framework. This can been seen with 1->0..1 and *->1 relationships which may generate error messages like "'System.Web.UI.WebControls.EntityDataSourceWrapper' does not contain a property with the name 'Orders.OrderID'". Download and install this update to correct this issue.
PM, ASP.NET Team, Microsoft