How can I prevent a field from being copied to the client proxy in WCF RIA?

Is there a metadata attribute I can use to prevent a field from being accessible on the client in a WCF RIA services? I sure I have seen this before, but I'm drawing a blank and Google isn't helping. It would look something like

[MetadataType(typeof(User.UserMetadata))]
public partial class User
{
    internal sealed class UserMetadata
    {
        private UserM开发者_如何转开发etadata()
        {
        }

        public int Id { get; set; }

        [HideFromClientProxy]
        public string PasswordSalt { get; set; }
    }
}

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Use the [Exclude]-Attribute

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[Exclude]
public string PasswordSalt { get; set; }