MATLAB: OOP derive comm.CRCGenerator

I try to derive the CRCGenerator of the comm toolbox.

See: sample code

classdef crc < comm.CRCGenerator
      properties (Nontunable)
          CRCName
      end
end

The result is, that the new property CRCName remains hidden in disp() but is shown in properties().

I'm using MATLAB Version: 7.14.0.739 (R2012a) and Communications System Toolbox Version 5.2 (R2012a).

>> a = crc(); >> disp( a );

a =

System: lte.generic.crc 
Properties:
         Polynomial: [16 12 5 0]
  InitialConditions: 0          
  CheckSumsPerFrame: 1

>> properties( a );

Properties for class lte.generic.crc:

    CRCName
    Polynomial
    InitialConditions
    CheckSumsPerFrame