VS.NET: Cannot implicitly convert type ‘SomeType[]’ to ‘System.Collections.ObjectModel.ObservableCollection<[Namespace].SomeType>’

There seems to be a known bug / issue in Visual Studio 2010 RC when dealing with Service References (to a WCF Service). The Collection Type of the Service Reference is set to custom and you start getting compilation errors like:
Cannot implicitly convert type ‘SomeType[]’ to ‘System.Collections.ObjectModel.ObservableCollection<[Namespace].SomeType>’   
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To get rid of this annoying error, just choose Configure Service Reference and select either Array or follow on of the instructions which are described here. I decided to use the ExtensionMethod way..

As confirmed by one of the Microsoft Product guys, this bug is killed in the final Version of Visual Studio 2010 – which should have been released yesterday .. according to rumors the RTM is detailed.. 



Configure Service Reference Dialog Box @msdn.microsoft.com

ObservableCollection missing as Collection Type in WCF since VS 2010 RC

VS2010 RC – WCF ObservableCollection is missing in Service Reference