.NET bug with max-constituent-size

I am using the netapp-manageability-sdk-5.7-dotnet-bindings (with ontapp-9-2.dll). I am trying to resize a volume:


                var volumeAttributes = new VolumeAttributes
                    VolumeIdAttributes = new VolumeIdAttributes { Name = volume.VolumeIdAttributes.Name }
                var modify = new VolumeModifyIter
                    Attributes = new VolumeAttributes
                        VolumeSpaceAttributes = new VolumeSpaceAttributes { Size = 201326592000M }
                    Query = volumeAttributes
                var result = modify.Invoke(server);

However, the XML that is sent to the controller looks like this (captured using log4net):




The volume is not resized and the API returns "Modification of the following fields: max-constituent-size not allowed for volumes of the type \"Flexible Volume - Read-Write volume\"." in the failure details. Obviously none of my code is modifying the value for MaxConsituentSize, which is what the API is complaining about. 


I beleive the problem is VolumeSpaceAttributes.MaxConstituentSize is a decimal instead of a nullable decimal (decimal?).


Has anyone found a workaround for this?


So far I've tried:

Setting MaxConsistuentSize to -1, 0

Inheriting from VolumeSpaceAttributes and overrriding the property to a nullable decimal (would not serialize)