Missing BigInteger features under F# Silverlight

I understand that certain .NET features are not available under Silverlight, but I've noticed that BigInteger under F# Silverlight has less features than advertised on MSDN. For example, MSDN says the explicit BigInteger to UInt16 method and several others should be available, yet F# only shows op_Explicit overloads for alias' int32, int64, and float.

What am I missing here? Could this have something 开发者_如何学运维to do with F#'s .NET 2.0 compatible big integer implementation? Note that I am using Silverlight 4.0 with corresponding Silverlight 4.0 F# assemblies.

The FSharp.Core Silverlight 4.0 build contains its own System.Numerics.BigInteger implementation, similar to how the F# for .NET 2.0 build does. But there is a System.Numerics assembly available as part of the standard Silverlight 4.0 libraries (referenced in the MSDN docs) so I am not sure why F# need include its own. I think this is a "bug" and will file a report.