3.1.5.1.12 Mapping Null Object
A Null Object in Classes and Arrays MUST be serialized using ObjectNull, ObjectNullMultiple or ObjectNullMultiple256 records, as specified in [MS-NRBF]. A Null Object in Arguments inlined in the BinaryMethodCall or BinaryMethodReturn record, as specified in [MS-NRBF], MUST be serialized as ValueWithCode, as specifed in [MS-NRBF] section 2.2.2.1, with the value of the PrimitiveTypeEnum field set to 17 (Null).