You should be able to simplify the query a bit by starting from the FF_QuotationDetails endpoint and accessing the FF_Item referenced by each FF_QuotationDetail. The query would look like this:
items = (From quotation
Where quotation.FF_Item.GroupID = ItemID _
quotation.FF_Item.ID, quotation.FF_Item.ItemName, quotation.FF_Item.Price, quotation.FF_Item.Rate, quotation.Quantity, quotation.TotalCost).ToList()
I hope that helps.
the Telerik team
Q1’11 SP1 of Telerik OpenAccess is available for download
; also available is the Q2'11 Roadmap
for Telerik OpenAccess ORM.